<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019fd2c8-6d31-73cd-9b17-dc297b807b8f,g:34e8fb5a-3815-4c83-9f9c-eff191ba3cf0-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.galaxy.com/role/CoverPage" xlink:type="simple" xlink:href="glxy-20260630.xsd#CoverPage"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/CoverPage" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitiesTable_019fd2c8-7159-7d0a-a97d-bec634e24499" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_EntitiesTable_019fd2c8-7159-7d0a-a97d-bec634e24499" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7159-7d03-bdbf-ebab503474c7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_019fd2c8-7159-7d0a-a97d-bec634e24499" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7159-7d03-bdbf-ebab503474c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-7d03-bdbf-ebab503474c7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7159-7d03-bdbf-ebab503474c7" xlink:to="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-7d03-bdbf-ebab503474c7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-76af-9b45-64a20bdda8c9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7159-7d03-bdbf-ebab503474c7" xlink:to="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-76af-9b45-64a20bdda8c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_019fd2c8-7159-749a-911f-4ebe7950fc78" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-76af-9b45-64a20bdda8c9" xlink:to="loc_us-gaap_CommonClassAMember_019fd2c8-7159-749a-911f-4ebe7950fc78" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassBMember_019fd2c8-7159-7ad7-a406-848b4ecdd4af" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonClassBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-76af-9b45-64a20bdda8c9" xlink:to="loc_us-gaap_CommonClassBMember_019fd2c8-7159-7ad7-a406-848b4ecdd4af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_019fd2c8-7159-732f-ae79-0492826b5f6e" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_DocumentType_019fd2c8-7159-732f-ae79-0492826b5f6e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentQuarterlyReport_019fd2c8-7159-7261-a4ab-926ddde6e32f" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentQuarterlyReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_DocumentQuarterlyReport_019fd2c8-7159-7261-a4ab-926ddde6e32f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_019fd2c8-7159-74d0-8d54-256884a01f39" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_DocumentPeriodEndDate_019fd2c8-7159-74d0-8d54-256884a01f39" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentTransitionReport_019fd2c8-7159-7596-879e-2d849b80554e" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentTransitionReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_DocumentTransitionReport_019fd2c8-7159-7596-879e-2d849b80554e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_019fd2c8-7159-79b1-b4a8-bc9117ae0953" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_EntityFileNumber_019fd2c8-7159-79b1-b4a8-bc9117ae0953" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_019fd2c8-7159-7d69-9ecc-f49acda75b16" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_EntityRegistrantName_019fd2c8-7159-7d69-9ecc-f49acda75b16" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_019fd2c8-7159-724c-a25a-53cc702221f7" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_EntityIncorporationStateCountryCode_019fd2c8-7159-724c-a25a-53cc702221f7" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_019fd2c8-7159-7030-a619-6b98047112b2" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_EntityTaxIdentificationNumber_019fd2c8-7159-7030-a619-6b98047112b2" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_019fd2c8-7159-7c5b-a2d3-2b85c36eac87" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_EntityAddressAddressLine1_019fd2c8-7159-7c5b-a2d3-2b85c36eac87" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_019fd2c8-7159-728d-9469-19fb00f76d71" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_EntityAddressCityOrTown_019fd2c8-7159-728d-9469-19fb00f76d71" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_019fd2c8-7159-731f-8e55-f371e7ed88c5" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_EntityAddressStateOrProvince_019fd2c8-7159-731f-8e55-f371e7ed88c5" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_019fd2c8-7159-77f4-95f1-1b53b19b155e" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_EntityAddressPostalZipCode_019fd2c8-7159-77f4-95f1-1b53b19b155e" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_019fd2c8-7159-7a95-93e6-c2a47957152e" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_CityAreaCode_019fd2c8-7159-7a95-93e6-c2a47957152e" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_019fd2c8-7159-7b2a-a6cf-e27eef496cff" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_LocalPhoneNumber_019fd2c8-7159-7b2a-a6cf-e27eef496cff" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_019fd2c8-7159-711f-b984-7171570da61c" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_Security12bTitle"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_Security12bTitle_019fd2c8-7159-711f-b984-7171570da61c" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_019fd2c8-7159-7950-ab97-56dbf683eb77" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_TradingSymbol"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_TradingSymbol_019fd2c8-7159-7950-ab97-56dbf683eb77" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_019fd2c8-7159-7c5f-a1fb-103c0350bde3" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SecurityExchangeName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_SecurityExchangeName_019fd2c8-7159-7c5f-a1fb-103c0350bde3" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCurrentReportingStatus_019fd2c8-7159-7402-b00c-00475658d959" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCurrentReportingStatus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_EntityCurrentReportingStatus_019fd2c8-7159-7402-b00c-00475658d959" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInteractiveDataCurrent_019fd2c8-7159-7d0b-a931-9b63d4ae9614" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityInteractiveDataCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_EntityInteractiveDataCurrent_019fd2c8-7159-7d0b-a931-9b63d4ae9614" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFilerCategory_019fd2c8-7159-7268-8e9c-659ca63058e1" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityFilerCategory"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_EntityFilerCategory_019fd2c8-7159-7268-8e9c-659ca63058e1" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitySmallBusiness_019fd2c8-7159-770d-8183-d7d41e987df9" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntitySmallBusiness"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_EntitySmallBusiness_019fd2c8-7159-770d-8183-d7d41e987df9" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_019fd2c8-7159-77ac-8990-984cd3e038c2" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_EntityEmergingGrowthCompany_019fd2c8-7159-77ac-8990-984cd3e038c2" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityShellCompany_019fd2c8-7159-7afe-9d3a-e9427077ba2c" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityShellCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_EntityShellCompany_019fd2c8-7159-7afe-9d3a-e9427077ba2c" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_019fd2c8-7159-73f7-934d-6204c257b798" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_019fd2c8-7159-73f7-934d-6204c257b798" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_019fd2c8-7159-743e-8452-ae990eb1df07" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_AmendmentFlag_019fd2c8-7159-743e-8452-ae990eb1df07" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalYearFocus_019fd2c8-7159-73f5-a7fd-055bbcb9d611" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentFiscalYearFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_DocumentFiscalYearFocus_019fd2c8-7159-73f5-a7fd-055bbcb9d611" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalPeriodFocus_019fd2c8-7159-7607-820b-105296480f4b" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentFiscalPeriodFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_DocumentFiscalPeriodFocus_019fd2c8-7159-7607-820b-105296480f4b" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_019fd2c8-7159-72bf-b7cd-292dd6389f1c" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_EntityCentralIndexKey_019fd2c8-7159-72bf-b7cd-292dd6389f1c" xlink:type="arc" order="27"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate_019fd2c8-7159-7114-9026-be5e164f8a63" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CurrentFiscalYearEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fd2c8-7159-7c6c-92c0-78c1a9104b4d" xlink:to="loc_dei_CurrentFiscalYearEndDate_019fd2c8-7159-7114-9026-be5e164f8a63" xlink:type="arc" order="28"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/CondensedConsolidatedInterimStatementsofOperationsandOtherComprehensiveIncomeLoss" xlink:type="simple" xlink:href="glxy-20260630.xsd#CondensedConsolidatedInterimStatementsofOperationsandOtherComprehensiveIncomeLoss"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/CondensedConsolidatedInterimStatementsofOperationsandOtherComprehensiveIncomeLoss" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019fd2c8-7159-70d0-9987-8745dcdb1151" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019fd2c8-7159-7fe5-b9a9-d383619ff39a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-70d0-9987-8745dcdb1151" xlink:to="loc_us-gaap_StatementTable_019fd2c8-7159-7fe5-b9a9-d383619ff39a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7159-7206-a29b-35eec9163761" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019fd2c8-7159-7fe5-b9a9-d383619ff39a" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7159-7206-a29b-35eec9163761" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-7206-a29b-35eec9163761_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7159-7206-a29b-35eec9163761" xlink:to="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-7206-a29b-35eec9163761_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-7c2e-af24-595fa527edb8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7159-7206-a29b-35eec9163761" xlink:to="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-7c2e-af24-595fa527edb8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_019fd2c8-7159-7b80-b189-dd0a0e6b6b69" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-7c2e-af24-595fa527edb8" xlink:to="loc_us-gaap_CommonClassAMember_019fd2c8-7159-7b80-b189-dd0a0e6b6b69" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_019fd2c8-7159-78b0-ba83-2dc5b194d049" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-70d0-9987-8745dcdb1151" xlink:to="loc_us-gaap_Revenues_019fd2c8-7159-78b0-ba83-2dc5b194d049" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_GainsLossesFromOperations_019fd2c8-7159-7fa6-b4cd-7bc52bc62ffa" xlink:href="glxy-20260630.xsd#glxy_GainsLossesFromOperations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-70d0-9987-8745dcdb1151" xlink:to="loc_glxy_GainsLossesFromOperations_019fd2c8-7159-7fa6-b4cd-7bc52bc62ffa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DataCenterLeasingRevenue_019fd2c8-7159-74fc-bcb2-3b6cc062b40f" xlink:href="glxy-20260630.xsd#glxy_DataCenterLeasingRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-70d0-9987-8745dcdb1151" xlink:to="loc_glxy_DataCenterLeasingRevenue_019fd2c8-7159-74fc-bcb2-3b6cc062b40f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_RevenuesAndGainsLossesFromOperations_019fd2c8-7159-7839-9f0d-664a537f6ea7" xlink:href="glxy-20260630.xsd#glxy_RevenuesAndGainsLossesFromOperations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-70d0-9987-8745dcdb1151" xlink:to="loc_glxy_RevenuesAndGainsLossesFromOperations_019fd2c8-7159-7839-9f0d-664a537f6ea7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpensesAbstract_019fd2c8-7159-726b-9f96-08a7a461bd7f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingExpensesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-70d0-9987-8745dcdb1151" xlink:to="loc_us-gaap_OperatingExpensesAbstract_019fd2c8-7159-726b-9f96-08a7a461bd7f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_TransactionExpenses_019fd2c8-7159-7cd9-aead-6cd38544b111" xlink:href="glxy-20260630.xsd#glxy_TransactionExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019fd2c8-7159-726b-9f96-08a7a461bd7f" xlink:to="loc_glxy_TransactionExpenses_019fd2c8-7159-7cd9-aead-6cd38544b111" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetImpairmentCharges_019fd2c8-7159-7b4b-8fff-a30234829c64" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetImpairmentCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019fd2c8-7159-726b-9f96-08a7a461bd7f" xlink:to="loc_us-gaap_AssetImpairmentCharges_019fd2c8-7159-7b4b-8fff-a30234829c64" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LaborAndRelatedExpense_019fd2c8-7159-7058-865c-e59a40f1d61f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LaborAndRelatedExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019fd2c8-7159-726b-9f96-08a7a461bd7f" xlink:to="loc_us-gaap_LaborAndRelatedExpense_019fd2c8-7159-7058-865c-e59a40f1d61f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_019fd2c8-7159-7df3-b553-aad9bdeee60c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019fd2c8-7159-726b-9f96-08a7a461bd7f" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_019fd2c8-7159-7df3-b553-aad9bdeee60c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_019fd2c8-7159-7cec-8a82-92f5e219b536" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019fd2c8-7159-726b-9f96-08a7a461bd7f" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_019fd2c8-7159-7cec-8a82-92f5e219b536" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommunicationsAndInformationTechnology_019fd2c8-7159-736c-bef6-4d9fd922c47e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommunicationsAndInformationTechnology"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019fd2c8-7159-726b-9f96-08a7a461bd7f" xlink:to="loc_us-gaap_CommunicationsAndInformationTechnology_019fd2c8-7159-736c-bef6-4d9fd922c47e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfessionalFees_019fd2c8-7159-7fa5-9c71-7b749de61f93" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfessionalFees"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019fd2c8-7159-726b-9f96-08a7a461bd7f" xlink:to="loc_us-gaap_ProfessionalFees_019fd2c8-7159-7fa5-9c71-7b749de61f93" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDebt_019fd2c8-7159-7734-a411-e96fb641cd78" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019fd2c8-7159-726b-9f96-08a7a461bd7f" xlink:to="loc_us-gaap_InterestExpenseDebt_019fd2c8-7159-7734-a411-e96fb641cd78" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenses_019fd2c8-7159-7907-8c9b-ba6718d3266c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019fd2c8-7159-726b-9f96-08a7a461bd7f" xlink:to="loc_us-gaap_OperatingExpenses_019fd2c8-7159-7907-8c9b-ba6718d3266c" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIncomeAndExpensesAbstract_019fd2c8-7159-7e96-82df-348e19e2112d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherIncomeAndExpensesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-70d0-9987-8745dcdb1151" xlink:to="loc_us-gaap_OtherIncomeAndExpensesAbstract_019fd2c8-7159-7e96-82df-348e19e2112d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrealizedGainLossOnDerivatives_019fd2c8-7159-7886-ade4-e11a9948ff2c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UnrealizedGainLossOnDerivatives"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherIncomeAndExpensesAbstract_019fd2c8-7159-7e96-82df-348e19e2112d" xlink:to="loc_us-gaap_UnrealizedGainLossOnDerivatives_019fd2c8-7159-7886-ade4-e11a9948ff2c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_019fd2c8-7159-7f6b-8f46-50c6be40b51b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherIncomeAndExpensesAbstract_019fd2c8-7159-7e96-82df-348e19e2112d" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_019fd2c8-7159-7f6b-8f46-50c6be40b51b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_019fd2c8-7159-7262-81c6-2cab6d301b92" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherIncomeAndExpensesAbstract_019fd2c8-7159-7e96-82df-348e19e2112d" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_019fd2c8-7159-7262-81c6-2cab6d301b92" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019fd2c8-7159-7ede-a63c-7325b02f20bf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-70d0-9987-8745dcdb1151" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019fd2c8-7159-7ede-a63c-7325b02f20bf" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_019fd2c8-7159-7e08-8d51-4458bb6cbf67" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-70d0-9987-8745dcdb1151" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_019fd2c8-7159-7e08-8d51-4458bb6cbf67" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_019fd2c8-7159-7359-948d-17559e17024e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-70d0-9987-8745dcdb1151" xlink:to="loc_us-gaap_ProfitLoss_019fd2c8-7159-7359-948d-17559e17024e" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_019fd2c8-7159-73bf-a67e-1bc8e79015da" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-70d0-9987-8745dcdb1151" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_019fd2c8-7159-73bf-a67e-1bc8e79015da" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTaxParent_019fd2c8-7159-7172-9457-5c61cf23764c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTaxParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_019fd2c8-7159-73bf-a67e-1bc8e79015da" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTaxParent_019fd2c8-7159-7172-9457-5c61cf23764c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019fd2c8-7159-708b-a24d-5f4e450f2217" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_019fd2c8-7159-73bf-a67e-1bc8e79015da" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019fd2c8-7159-708b-a24d-5f4e450f2217" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_019fd2c8-7159-7266-9910-3658516fca74" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ComprehensiveIncomeNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-70d0-9987-8745dcdb1151" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_019fd2c8-7159-7266-9910-3658516fca74" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_ComprehensiveIncomeLossNetOfTaxAttributableToClassBUnitHolders_019fd2c8-7159-7d29-84d9-d22da68b46ea" xlink:href="glxy-20260630.xsd#glxy_ComprehensiveIncomeLossNetOfTaxAttributableToClassBUnitHolders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-70d0-9987-8745dcdb1151" xlink:to="loc_glxy_ComprehensiveIncomeLossNetOfTaxAttributableToClassBUnitHolders_019fd2c8-7159-7d29-84d9-d22da68b46ea" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_ComprehensiveIncomeLossNetOfTaxAttributableToNonredeemableInterest_019fd2c8-7159-7543-8fd6-2889d8c965e6" xlink:href="glxy-20260630.xsd#glxy_ComprehensiveIncomeLossNetOfTaxAttributableToNonredeemableInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-70d0-9987-8745dcdb1151" xlink:to="loc_glxy_ComprehensiveIncomeLossNetOfTaxAttributableToNonredeemableInterest_019fd2c8-7159-7543-8fd6-2889d8c965e6" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_ComprehensiveIncomeLossNetOfTaxAttributableToClassACommonStockholders_019fd2c8-7159-7335-8f3c-df389e5d8ac9" xlink:href="glxy-20260630.xsd#glxy_ComprehensiveIncomeLossNetOfTaxAttributableToClassACommonStockholders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-70d0-9987-8745dcdb1151" xlink:to="loc_glxy_ComprehensiveIncomeLossNetOfTaxAttributableToClassACommonStockholders_019fd2c8-7159-7335-8f3c-df389e5d8ac9" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract_019fd2c8-7159-7baa-a64b-f10386a6ca42" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-70d0-9987-8745dcdb1151" xlink:to="loc_us-gaap_EarningsPerShareAbstract_019fd2c8-7159-7baa-a64b-f10386a6ca42" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019fd2c8-7159-70db-94a4-18b5c50b4e86" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_019fd2c8-7159-7baa-a64b-f10386a6ca42" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019fd2c8-7159-70db-94a4-18b5c50b4e86" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_019fd2c8-7159-7dcf-aec5-4f429cce3384" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_019fd2c8-7159-7baa-a64b-f10386a6ca42" xlink:to="loc_us-gaap_EarningsPerShareBasic_019fd2c8-7159-7dcf-aec5-4f429cce3384" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_019fd2c8-7159-731a-8146-4462d309d54e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_019fd2c8-7159-7baa-a64b-f10386a6ca42" xlink:to="loc_us-gaap_EarningsPerShareDiluted_019fd2c8-7159-731a-8146-4462d309d54e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract_019fd2c8-7159-755a-99ca-a3f967992864" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-70d0-9987-8745dcdb1151" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract_019fd2c8-7159-755a-99ca-a3f967992864" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019fd2c8-7159-7c6b-8e19-5f787110cc51" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract_019fd2c8-7159-755a-99ca-a3f967992864" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019fd2c8-7159-7c6b-8e19-5f787110cc51" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019fd2c8-7159-7ad3-aa81-c6396804ae9b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract_019fd2c8-7159-755a-99ca-a3f967992864" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019fd2c8-7159-7ad3-aa81-c6396804ae9b" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/CondensedConsolidatedInterimStatementsofFinancialPosition" xlink:type="simple" xlink:href="glxy-20260630.xsd#CondensedConsolidatedInterimStatementsofFinancialPosition"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/CondensedConsolidatedInterimStatementsofFinancialPosition" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019fd2c8-7159-7e37-9142-4418cbb5a1f3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019fd2c8-7159-7bbf-920f-904ab07f18e3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-7e37-9142-4418cbb5a1f3" xlink:to="loc_us-gaap_StatementTable_019fd2c8-7159-7bbf-920f-904ab07f18e3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7159-71a7-9849-e412b94ea295" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019fd2c8-7159-7bbf-920f-904ab07f18e3" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7159-71a7-9849-e412b94ea295" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-71a7-9849-e412b94ea295_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7159-71a7-9849-e412b94ea295" xlink:to="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-71a7-9849-e412b94ea295_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-7662-9fa3-3dc873278231" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7159-71a7-9849-e412b94ea295" xlink:to="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-7662-9fa3-3dc873278231" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_019fd2c8-7159-78ba-bc03-f8d7d1b904c0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-7662-9fa3-3dc873278231" xlink:to="loc_us-gaap_CommonClassAMember_019fd2c8-7159-78ba-bc03-f8d7d1b904c0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_ConvertibleClassBCommonStockMember_019fd2c8-7159-774b-bff1-e7ddf7083d1f" xlink:href="glxy-20260630.xsd#glxy_ConvertibleClassBCommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-7662-9fa3-3dc873278231" xlink:to="loc_glxy_ConvertibleClassBCommonStockMember_019fd2c8-7159-774b-bff1-e7ddf7083d1f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_019fd2c8-7159-7e60-9b40-50e1c91444b9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-7e37-9142-4418cbb5a1f3" xlink:to="loc_us-gaap_AssetsAbstract_019fd2c8-7159-7e60-9b40-50e1c91444b9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrentAbstract_019fd2c8-7159-755b-b70e-1b545ed59d8f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019fd2c8-7159-7e60-9b40-50e1c91444b9" xlink:to="loc_us-gaap_AssetsCurrentAbstract_019fd2c8-7159-755b-b70e-1b545ed59d8f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019fd2c8-7159-7ea7-a211-8a093e0e2880" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019fd2c8-7159-755b-b70e-1b545ed59d8f" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019fd2c8-7159-7ea7-a211-8a093e0e2880" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetIntangibleAssetsCurrent_019fd2c8-7159-7f27-a603-145ef138ef97" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetIntangibleAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019fd2c8-7159-755b-b70e-1b545ed59d8f" xlink:to="loc_glxy_CryptoAssetIntangibleAssetsCurrent_019fd2c8-7159-7f27-a603-145ef138ef97" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetFinancialAssetCurrent_019fd2c8-7159-79b9-825f-0707decaefc0" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetFinancialAssetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019fd2c8-7159-755b-b70e-1b545ed59d8f" xlink:to="loc_glxy_CryptoAssetFinancialAssetCurrent_019fd2c8-7159-79b9-825f-0707decaefc0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesAndLoansReceivableNetCurrent_019fd2c8-7159-7b72-8689-5f912637e550" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesAndLoansReceivableNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019fd2c8-7159-755b-b70e-1b545ed59d8f" xlink:to="loc_us-gaap_NotesAndLoansReceivableNetCurrent_019fd2c8-7159-7b72-8689-5f912637e550" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermInvestments_019fd2c8-7159-7a25-ba48-aca53846ec03" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019fd2c8-7159-755b-b70e-1b545ed59d8f" xlink:to="loc_us-gaap_ShortTermInvestments_019fd2c8-7159-7a25-ba48-aca53846ec03" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_AssetsPostedAsCollateralCurrent_019fd2c8-7159-7673-9026-a8c301e30d71" xlink:href="glxy-20260630.xsd#glxy_AssetsPostedAsCollateralCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019fd2c8-7159-755b-b70e-1b545ed59d8f" xlink:to="loc_glxy_AssetsPostedAsCollateralCurrent_019fd2c8-7159-7673-9026-a8c301e30d71" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssetsCurrent_019fd2c8-7159-7641-98cc-245f5960efc4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019fd2c8-7159-755b-b70e-1b545ed59d8f" xlink:to="loc_us-gaap_DerivativeAssetsCurrent_019fd2c8-7159-7641-98cc-245f5960efc4" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_019fd2c8-7159-71cf-91b9-6cdbd1984739" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019fd2c8-7159-755b-b70e-1b545ed59d8f" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_019fd2c8-7159-71cf-91b9-6cdbd1984739" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetReceivableRestrictedCurrent_019fd2c8-7159-76ca-9f09-8bef722722b8" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetReceivableRestrictedCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019fd2c8-7159-755b-b70e-1b545ed59d8f" xlink:to="loc_glxy_CryptoAssetReceivableRestrictedCurrent_019fd2c8-7159-76ca-9f09-8bef722722b8" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLossCurrent_019fd2c8-7159-7865-9748-1b2bba721268" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLossCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019fd2c8-7159-755b-b70e-1b545ed59d8f" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLossCurrent_019fd2c8-7159-7865-9748-1b2bba721268" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_019fd2c8-7159-71c2-a8d0-b72f1bfb846e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019fd2c8-7159-755b-b70e-1b545ed59d8f" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_019fd2c8-7159-71c2-a8d0-b72f1bfb846e" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_019fd2c8-7159-77a3-8958-c9b8a03e738e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019fd2c8-7159-755b-b70e-1b545ed59d8f" xlink:to="loc_us-gaap_AssetsCurrent_019fd2c8-7159-77a3-8958-c9b8a03e738e" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsNoncurrentAbstract_019fd2c8-7159-7e68-92be-c8cbff3de866" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsNoncurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019fd2c8-7159-7e60-9b40-50e1c91444b9" xlink:to="loc_us-gaap_AssetsNoncurrentAbstract_019fd2c8-7159-7e68-92be-c8cbff3de866" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetReceivableRestrictedNoncurrent_019fd2c8-7159-761d-8119-d8d7b677189e" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetReceivableRestrictedNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_019fd2c8-7159-7e68-92be-c8cbff3de866" xlink:to="loc_glxy_CryptoAssetReceivableRestrictedNoncurrent_019fd2c8-7159-761d-8119-d8d7b677189e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetLoanReceivableRestrictedNoncurrent_019fd2c8-7159-7c1c-813a-6a85b32beb20" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetLoanReceivableRestrictedNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_019fd2c8-7159-7e68-92be-c8cbff3de866" xlink:to="loc_glxy_CryptoAssetLoanReceivableRestrictedNoncurrent_019fd2c8-7159-7c1c-813a-6a85b32beb20" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermInvestments_019fd2c8-7159-7867-8eed-827cb37c35af" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_019fd2c8-7159-7e68-92be-c8cbff3de866" xlink:to="loc_us-gaap_LongTermInvestments_019fd2c8-7159-7867-8eed-827cb37c35af" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetIntangibleAssetNoncurrent_019fd2c8-7159-76f5-b66d-0174f84a686c" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetIntangibleAssetNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_019fd2c8-7159-7e68-92be-c8cbff3de866" xlink:to="loc_glxy_CryptoAssetIntangibleAssetNoncurrent_019fd2c8-7159-76f5-b66d-0174f84a686c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLossNoncurrent_019fd2c8-7159-74a6-b98e-5a9807648c9c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLossNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_019fd2c8-7159-7e68-92be-c8cbff3de866" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLossNoncurrent_019fd2c8-7159-74a6-b98e-5a9807648c9c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_019fd2c8-7159-7f4d-a804-9beb6c88032d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_019fd2c8-7159-7e68-92be-c8cbff3de866" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_019fd2c8-7159-7f4d-a804-9beb6c88032d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_019fd2c8-7159-79b7-a9c4-ae887f155117" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_019fd2c8-7159-7e68-92be-c8cbff3de866" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_019fd2c8-7159-79b7-a9c4-ae887f155117" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_019fd2c8-7159-7348-b267-84329d835909" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_019fd2c8-7159-7e68-92be-c8cbff3de866" xlink:to="loc_us-gaap_Goodwill_019fd2c8-7159-7348-b267-84329d835909" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsNoncurrent_019fd2c8-7159-7cc4-8b8a-c99a8b1fbfe9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_019fd2c8-7159-7e68-92be-c8cbff3de866" xlink:to="loc_us-gaap_AssetsNoncurrent_019fd2c8-7159-7cc4-8b8a-c99a8b1fbfe9" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_019fd2c8-7159-75e4-b098-39c0f20c0712" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019fd2c8-7159-7e60-9b40-50e1c91444b9" xlink:to="loc_us-gaap_Assets_019fd2c8-7159-75e4-b098-39c0f20c0712" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019fd2c8-7159-7903-a0b0-786984c15831" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-7e37-9142-4418cbb5a1f3" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019fd2c8-7159-7903-a0b0-786984c15831" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_019fd2c8-7159-702c-ad74-fbd82c156c43" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019fd2c8-7159-7903-a0b0-786984c15831" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_019fd2c8-7159-702c-ad74-fbd82c156c43" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilitiesCurrent_019fd2c8-7159-7bcb-b8ed-4733231ff0e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019fd2c8-7159-702c-ad74-fbd82c156c43" xlink:to="loc_us-gaap_DerivativeLiabilitiesCurrent_019fd2c8-7159-7bcb-b8ed-4733231ff0e1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_019fd2c8-7159-701f-a35a-5c5bff2d6eb8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019fd2c8-7159-702c-ad74-fbd82c156c43" xlink:to="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_019fd2c8-7159-701f-a35a-5c5bff2d6eb8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetPayableCurrent_019fd2c8-7159-72d9-8c04-db8e575159c1" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019fd2c8-7159-702c-ad74-fbd82c156c43" xlink:to="loc_glxy_CryptoAssetPayableCurrent_019fd2c8-7159-72d9-8c04-db8e575159c1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_PayableToCustomersCash_019fd2c8-7159-7554-96b3-da0f68f549b1" xlink:href="glxy-20260630.xsd#glxy_PayableToCustomersCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019fd2c8-7159-702c-ad74-fbd82c156c43" xlink:to="loc_glxy_PayableToCustomersCash_019fd2c8-7159-7554-96b3-da0f68f549b1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansPayableCurrent_019fd2c8-7159-7696-9eac-aa6d66628e7f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LoansPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019fd2c8-7159-702c-ad74-fbd82c156c43" xlink:to="loc_us-gaap_LoansPayableCurrent_019fd2c8-7159-7696-9eac-aa6d66628e7f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CollateralPayableCurrent_019fd2c8-7159-719e-a527-481809f18301" xlink:href="glxy-20260630.xsd#glxy_CollateralPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019fd2c8-7159-702c-ad74-fbd82c156c43" xlink:to="loc_glxy_CollateralPayableCurrent_019fd2c8-7159-719e-a527-481809f18301" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableCurrent_019fd2c8-7159-7006-b304-b10e57818725" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019fd2c8-7159-702c-ad74-fbd82c156c43" xlink:to="loc_us-gaap_NotesPayableCurrent_019fd2c8-7159-7006-b304-b10e57818725" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesCurrent_019fd2c8-7159-75ac-a279-71662e522af4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019fd2c8-7159-702c-ad74-fbd82c156c43" xlink:to="loc_us-gaap_OtherLiabilitiesCurrent_019fd2c8-7159-75ac-a279-71662e522af4" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_019fd2c8-7159-7dcc-944b-baf7e65fd485" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019fd2c8-7159-702c-ad74-fbd82c156c43" xlink:to="loc_us-gaap_LiabilitiesCurrent_019fd2c8-7159-7dcc-944b-baf7e65fd485" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesNoncurrentAbstract_019fd2c8-7159-7a24-bf3c-d70a5f8a8e64" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesNoncurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019fd2c8-7159-7903-a0b0-786984c15831" xlink:to="loc_us-gaap_LiabilitiesNoncurrentAbstract_019fd2c8-7159-7a24-bf3c-d70a5f8a8e64" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermNotesPayable_019fd2c8-7159-7c26-aaec-61c3e42dfc62" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermNotesPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_019fd2c8-7159-7a24-bf3c-d70a5f8a8e64" xlink:to="loc_us-gaap_LongTermNotesPayable_019fd2c8-7159-7c26-aaec-61c3e42dfc62" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetPayableNoncurrent_019fd2c8-7159-7dca-b692-37258ffe6a29" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetPayableNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_019fd2c8-7159-7a24-bf3c-d70a5f8a8e64" xlink:to="loc_glxy_CryptoAssetPayableNoncurrent_019fd2c8-7159-7dca-b692-37258ffe6a29" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_019fd2c8-7159-7d80-8368-0b52eb50e5b4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_019fd2c8-7159-7a24-bf3c-d70a5f8a8e64" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_019fd2c8-7159-7d80-8368-0b52eb50e5b4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesNoncurrent_019fd2c8-7159-71fc-8a67-d84c30218399" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_019fd2c8-7159-7a24-bf3c-d70a5f8a8e64" xlink:to="loc_us-gaap_LiabilitiesNoncurrent_019fd2c8-7159-71fc-8a67-d84c30218399" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_019fd2c8-7159-783f-aef7-d2fd4fed90e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Liabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019fd2c8-7159-7903-a0b0-786984c15831" xlink:to="loc_us-gaap_Liabilities_019fd2c8-7159-783f-aef7-d2fd4fed90e1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies_019fd2c8-7159-70af-ba04-2c6cc50071f8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019fd2c8-7159-7903-a0b0-786984c15831" xlink:to="loc_us-gaap_CommitmentsAndContingencies_019fd2c8-7159-70af-ba04-2c6cc50071f8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityAbstract_019fd2c8-7159-7972-bb05-f5dae8f9ba3f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019fd2c8-7159-7903-a0b0-786984c15831" xlink:to="loc_us-gaap_StockholdersEquityAbstract_019fd2c8-7159-7972-bb05-f5dae8f9ba3f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_019fd2c8-7159-7118-aecf-8a67b6b2dfba" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019fd2c8-7159-7972-bb05-f5dae8f9ba3f" xlink:to="loc_us-gaap_CommonStockValue_019fd2c8-7159-7118-aecf-8a67b6b2dfba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapital_019fd2c8-7159-7764-a368-63931453c5db" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019fd2c8-7159-7972-bb05-f5dae8f9ba3f" xlink:to="loc_us-gaap_AdditionalPaidInCapital_019fd2c8-7159-7764-a368-63931453c5db" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_019fd2c8-7159-7b26-8fb8-e3dcf291397f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019fd2c8-7159-7972-bb05-f5dae8f9ba3f" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_019fd2c8-7159-7b26-8fb8-e3dcf291397f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019fd2c8-7159-75ab-8028-9e5f25da515e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019fd2c8-7159-7972-bb05-f5dae8f9ba3f" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019fd2c8-7159-75ab-8028-9e5f25da515e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019fd2c8-7159-7b2e-ad0f-cce4f39f4f4e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019fd2c8-7159-7972-bb05-f5dae8f9ba3f" xlink:to="loc_us-gaap_StockholdersEquity_019fd2c8-7159-7b2e-ad0f-cce4f39f4f4e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterest_019fd2c8-7159-71e1-be6e-272ca4e59d66" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MinorityInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019fd2c8-7159-7972-bb05-f5dae8f9ba3f" xlink:to="loc_us-gaap_MinorityInterest_019fd2c8-7159-71e1-be6e-272ca4e59d66" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019fd2c8-7159-70f3-bdf6-aba3b1b7bba2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019fd2c8-7159-7972-bb05-f5dae8f9ba3f" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019fd2c8-7159-70f3-bdf6-aba3b1b7bba2" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_019fd2c8-7159-730c-9a11-b09d65bc052c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019fd2c8-7159-7903-a0b0-786984c15831" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_019fd2c8-7159-730c-9a11-b09d65bc052c" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/CondensedConsolidatedInterimStatementsofFinancialPositionParenthetical" xlink:type="simple" xlink:href="glxy-20260630.xsd#CondensedConsolidatedInterimStatementsofFinancialPositionParenthetical"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/CondensedConsolidatedInterimStatementsofFinancialPositionParenthetical" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019fd2c8-7159-7fe5-899b-c38715141e14" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019fd2c8-7159-7363-b324-9d0c09378f97" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-7fe5-899b-c38715141e14" xlink:to="loc_us-gaap_StatementTable_019fd2c8-7159-7363-b324-9d0c09378f97" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019fd2c8-7159-72db-91cf-c76221f6e2a9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019fd2c8-7159-7363-b324-9d0c09378f97" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019fd2c8-7159-72db-91cf-c76221f6e2a9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019fd2c8-7159-72db-91cf-c76221f6e2a9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019fd2c8-7159-72db-91cf-c76221f6e2a9" xlink:to="loc_us-gaap_RelatedPartyDomain_019fd2c8-7159-72db-91cf-c76221f6e2a9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019fd2c8-7159-766d-b244-db57ff0029fa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019fd2c8-7159-72db-91cf-c76221f6e2a9" xlink:to="loc_us-gaap_RelatedPartyDomain_019fd2c8-7159-766d-b244-db57ff0029fa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019fd2c8-7159-7421-9dec-e12b6c26ef51" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019fd2c8-7159-766d-b244-db57ff0029fa" xlink:to="loc_us-gaap_RelatedPartyMember_019fd2c8-7159-7421-9dec-e12b6c26ef51" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7159-766e-859a-77b1526ae42c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019fd2c8-7159-7363-b324-9d0c09378f97" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7159-766e-859a-77b1526ae42c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-766e-859a-77b1526ae42c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7159-766e-859a-77b1526ae42c" xlink:to="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-766e-859a-77b1526ae42c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-74e0-aeaa-63796b8a479a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7159-766e-859a-77b1526ae42c" xlink:to="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-74e0-aeaa-63796b8a479a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_019fd2c8-7159-7562-b92b-1a5364d7f425" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-74e0-aeaa-63796b8a479a" xlink:to="loc_us-gaap_CommonClassAMember_019fd2c8-7159-7562-b92b-1a5364d7f425" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_ConvertibleClassBCommonStockMember_019fd2c8-7159-7ad6-befe-f408fd3028c7" xlink:href="glxy-20260630.xsd#glxy_ConvertibleClassBCommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-74e0-aeaa-63796b8a479a" xlink:to="loc_glxy_ConvertibleClassBCommonStockMember_019fd2c8-7159-7ad6-befe-f408fd3028c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetIntangibleAssetsCurrentFairValue_019fd2c8-7159-7c05-a67c-550de039bde0" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetIntangibleAssetsCurrentFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-7fe5-899b-c38715141e14" xlink:to="loc_glxy_CryptoAssetIntangibleAssetsCurrentFairValue_019fd2c8-7159-7c05-a67c-550de039bde0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_019fd2c8-7159-7006-be91-a1460982a703" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-7fe5-899b-c38715141e14" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_019fd2c8-7159-7006-be91-a1460982a703" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsFairValueDisclosure_019fd2c8-7159-7694-a358-acc838d1d715" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-7fe5-899b-c38715141e14" xlink:to="loc_us-gaap_InvestmentsFairValueDisclosure_019fd2c8-7159-7694-a358-acc838d1d715" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_019fd2c8-7159-78bb-bd31-779e54778800" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-7fe5-899b-c38715141e14" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_019fd2c8-7159-78bb-bd31-779e54778800" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_019fd2c8-7159-7a67-a855-9fecbdacad6d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-7fe5-899b-c38715141e14" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_019fd2c8-7159-7a67-a855-9fecbdacad6d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_019fd2c8-7159-7bab-b19b-bcb4cccb42af" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-7fe5-899b-c38715141e14" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_019fd2c8-7159-7bab-b19b-bcb4cccb42af" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_019fd2c8-7159-707e-960f-6e69ed4a79a6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-7fe5-899b-c38715141e14" xlink:to="loc_us-gaap_CommonStockSharesIssued_019fd2c8-7159-707e-960f-6e69ed4a79a6" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019fd2c8-7159-72d9-b203-0a34508ea136" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-7fe5-899b-c38715141e14" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_019fd2c8-7159-72d9-b203-0a34508ea136" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/CondensedConsolidatedInterimStatementsofChangesinEquity" xlink:type="simple" xlink:href="glxy-20260630.xsd#CondensedConsolidatedInterimStatementsofChangesinEquity"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/CondensedConsolidatedInterimStatementsofChangesinEquity" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019fd2c8-7159-72fa-87bb-772bc8c612a4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019fd2c8-7159-7fe0-a699-c46193284cad" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-72fa-87bb-772bc8c612a4" xlink:to="loc_us-gaap_StatementTable_019fd2c8-7159-7fe0-a699-c46193284cad" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerCapitalComponentsAxis_019fd2c8-7159-7c6b-8b47-a69635217438" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PartnerCapitalComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019fd2c8-7159-7fe0-a699-c46193284cad" xlink:to="loc_us-gaap_PartnerCapitalComponentsAxis_019fd2c8-7159-7c6b-8b47-a69635217438" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerCapitalComponentsDomain_019fd2c8-7159-7c6b-8b47-a69635217438_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PartnerCapitalComponentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerCapitalComponentsAxis_019fd2c8-7159-7c6b-8b47-a69635217438" xlink:to="loc_us-gaap_PartnerCapitalComponentsDomain_019fd2c8-7159-7c6b-8b47-a69635217438_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerCapitalComponentsDomain_019fd2c8-7159-7d9b-9de8-68315894d11b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PartnerCapitalComponentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerCapitalComponentsAxis_019fd2c8-7159-7c6b-8b47-a69635217438" xlink:to="loc_us-gaap_PartnerCapitalComponentsDomain_019fd2c8-7159-7d9b-9de8-68315894d11b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalUnitsMember_019fd2c8-7159-7077-b4a4-3d76b5665e2c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerCapitalComponentsDomain_019fd2c8-7159-7d9b-9de8-68315894d11b" xlink:to="loc_us-gaap_CapitalUnitsMember_019fd2c8-7159-7077-b4a4-3d76b5665e2c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_019fd2c8-7159-789c-9153-4e5b2c0198a0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019fd2c8-7159-7fe0-a699-c46193284cad" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_019fd2c8-7159-789c-9153-4e5b2c0198a0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_019fd2c8-7159-789c-9153-4e5b2c0198a0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_019fd2c8-7159-789c-9153-4e5b2c0198a0" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_019fd2c8-7159-789c-9153-4e5b2c0198a0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_019fd2c8-7159-78f3-b931-5a6496dec813" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_019fd2c8-7159-789c-9153-4e5b2c0198a0" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_019fd2c8-7159-78f3-b931-5a6496dec813" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_ClassAUnitMember_019fd2c8-7159-7cf7-b997-323a41266dc3" xlink:href="glxy-20260630.xsd#glxy_ClassAUnitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_019fd2c8-7159-78f3-b931-5a6496dec813" xlink:to="loc_glxy_ClassAUnitMember_019fd2c8-7159-7cf7-b997-323a41266dc3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_ClassBUnitMember_019fd2c8-7159-760c-b7de-34cbdfb796fd" xlink:href="glxy-20260630.xsd#glxy_ClassBUnitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_019fd2c8-7159-78f3-b931-5a6496dec813" xlink:to="loc_glxy_ClassBUnitMember_019fd2c8-7159-760c-b7de-34cbdfb796fd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7159-7d09-ad73-cc4967795043" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019fd2c8-7159-7fe0-a699-c46193284cad" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7159-7d09-ad73-cc4967795043" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-7d09-ad73-cc4967795043_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7159-7d09-ad73-cc4967795043" xlink:to="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-7d09-ad73-cc4967795043_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-79f1-b642-ccd57d4af947" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7159-7d09-ad73-cc4967795043" xlink:to="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-79f1-b642-ccd57d4af947" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_019fd2c8-7159-7a3c-8af9-9b92a12c46da" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-79f1-b642-ccd57d4af947" xlink:to="loc_us-gaap_CommonClassAMember_019fd2c8-7159-7a3c-8af9-9b92a12c46da" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassBMember_019fd2c8-7159-7db9-968a-300b7bd4eb18" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonClassBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019fd2c8-7159-79f1-b642-ccd57d4af947" xlink:to="loc_us-gaap_CommonClassBMember_019fd2c8-7159-7db9-968a-300b7bd4eb18" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019fd2c8-7159-79b3-845a-2c20d97b18e4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019fd2c8-7159-7fe0-a699-c46193284cad" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019fd2c8-7159-79b3-845a-2c20d97b18e4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019fd2c8-7159-79b3-845a-2c20d97b18e4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019fd2c8-7159-79b3-845a-2c20d97b18e4" xlink:to="loc_us-gaap_EquityComponentDomain_019fd2c8-7159-79b3-845a-2c20d97b18e4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019fd2c8-7159-7917-8049-936ae96ea514" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019fd2c8-7159-79b3-845a-2c20d97b18e4" xlink:to="loc_us-gaap_EquityComponentDomain_019fd2c8-7159-7917-8049-936ae96ea514" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019fd2c8-7159-7e22-853b-5fe8386eecda" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019fd2c8-7159-7917-8049-936ae96ea514" xlink:to="loc_us-gaap_CommonStockMember_019fd2c8-7159-7e22-853b-5fe8386eecda" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_019fd2c8-7159-791f-84fc-ae27a7e173e5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019fd2c8-7159-7917-8049-936ae96ea514" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_019fd2c8-7159-791f-84fc-ae27a7e173e5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019fd2c8-7159-7a37-b35c-818607e0e3ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019fd2c8-7159-7917-8049-936ae96ea514" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019fd2c8-7159-7a37-b35c-818607e0e3ca" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_019fd2c8-7159-7695-a9b8-15c5b0012a5a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019fd2c8-7159-7917-8049-936ae96ea514" xlink:to="loc_us-gaap_RetainedEarningsMember_019fd2c8-7159-7695-a9b8-15c5b0012a5a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_019fd2c8-7159-75d3-b548-15c8cc9e3622" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019fd2c8-7159-7917-8049-936ae96ea514" xlink:to="loc_us-gaap_NoncontrollingInterestMember_019fd2c8-7159-75d3-b548-15c8cc9e3622" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_019fd2c8-7159-7b0f-8302-de09adbbef47" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInPartnersCapitalRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-72fa-87bb-772bc8c612a4" xlink:to="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_019fd2c8-7159-7b0f-8302-de09adbbef47" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAccountUnits_019fd2c8-7159-7bcb-8c0e-fb96bb1de4bb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PartnersCapitalAccountUnits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_019fd2c8-7159-7b0f-8302-de09adbbef47" xlink:to="loc_us-gaap_PartnersCapitalAccountUnits_019fd2c8-7159-7bcb-8c0e-fb96bb1de4bb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapital_019fd2c8-7159-7ef2-8fd4-f7f7b032c72d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PartnersCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_019fd2c8-7159-7b0f-8302-de09adbbef47" xlink:to="loc_us-gaap_PartnersCapital_019fd2c8-7159-7ef2-8fd4-f7f7b032c72d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAccountUnitBasedCompensation_019fd2c8-7159-7958-a1b5-6cdbaa83e90b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PartnersCapitalAccountUnitBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_019fd2c8-7159-7b0f-8302-de09adbbef47" xlink:to="loc_us-gaap_PartnersCapitalAccountUnitBasedCompensation_019fd2c8-7159-7958-a1b5-6cdbaa83e90b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountDistributionAmount_019fd2c8-7159-7d88-9461-27ef8edf786a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LimitedPartnersCapitalAccountDistributionAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_019fd2c8-7159-7b0f-8302-de09adbbef47" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountDistributionAmount_019fd2c8-7159-7d88-9461-27ef8edf786a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_PartnersCapitalUnitsCancelledInPeriod_019fd2c8-7159-7fd4-b527-6860cceca292" xlink:href="glxy-20260630.xsd#glxy_PartnersCapitalUnitsCancelledInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_019fd2c8-7159-7b0f-8302-de09adbbef47" xlink:to="loc_glxy_PartnersCapitalUnitsCancelledInPeriod_019fd2c8-7159-7fd4-b527-6860cceca292" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_PartnersCapitalValueCancelledInPeriod_019fd2c8-7159-7e99-9521-687fe191a768" xlink:href="glxy-20260630.xsd#glxy_PartnersCapitalValueCancelledInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_019fd2c8-7159-7b0f-8302-de09adbbef47" xlink:to="loc_glxy_PartnersCapitalValueCancelledInPeriod_019fd2c8-7159-7e99-9521-687fe191a768" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAccountUnitsSaleOfUnits_019fd2c8-7159-7a95-9fee-f943c2decfa9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PartnersCapitalAccountUnitsSaleOfUnits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_019fd2c8-7159-7b0f-8302-de09adbbef47" xlink:to="loc_us-gaap_PartnersCapitalAccountUnitsSaleOfUnits_019fd2c8-7159-7a95-9fee-f943c2decfa9" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAccountSaleOfUnits_019fd2c8-7159-784c-8ebb-3a96fd4031d1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PartnersCapitalAccountSaleOfUnits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_019fd2c8-7159-7b0f-8302-de09adbbef47" xlink:to="loc_us-gaap_PartnersCapitalAccountSaleOfUnits_019fd2c8-7159-784c-8ebb-3a96fd4031d1" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_NetIncomeLossAttributableToParentPreReorganization_019fd2c8-7159-7fab-918e-3940b82bb705" xlink:href="glxy-20260630.xsd#glxy_NetIncomeLossAttributableToParentPreReorganization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_019fd2c8-7159-7b0f-8302-de09adbbef47" xlink:to="loc_glxy_NetIncomeLossAttributableToParentPreReorganization_019fd2c8-7159-7fab-918e-3940b82bb705" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_ImpactOfReorganizationTransactionsInShares_019fd2c8-7159-79cb-842b-3ec366a7eb10" xlink:href="glxy-20260630.xsd#glxy_ImpactOfReorganizationTransactionsInShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_019fd2c8-7159-7b0f-8302-de09adbbef47" xlink:to="loc_glxy_ImpactOfReorganizationTransactionsInShares_019fd2c8-7159-79cb-842b-3ec366a7eb10" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_ImpactOfReorganizationTransactions_019fd2c8-7159-7d92-ba1b-f3e60c6209b2" xlink:href="glxy-20260630.xsd#glxy_ImpactOfReorganizationTransactions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_019fd2c8-7159-7b0f-8302-de09adbbef47" xlink:to="loc_glxy_ImpactOfReorganizationTransactions_019fd2c8-7159-7d92-ba1b-f3e60c6209b2" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalOther_019fd2c8-7159-7f8f-9cd0-f7d1c4780879" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PartnersCapitalOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_019fd2c8-7159-7b0f-8302-de09adbbef47" xlink:to="loc_us-gaap_PartnersCapitalOther_019fd2c8-7159-7f8f-9cd0-f7d1c4780879" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAccountUnits_019fd2c8-7159-753f-a37c-b39e87aa3d6b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PartnersCapitalAccountUnits"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapital_019fd2c8-7159-73dd-bf65-2ec3b947dfda" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PartnersCapital"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fd2c8-7159-70d7-9d81-4e0a06ba016f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019fd2c8-7159-72fa-87bb-772bc8c612a4" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fd2c8-7159-70d7-9d81-4e0a06ba016f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019fd2c8-7159-73ae-82fd-ed3ec6f9bade" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fd2c8-7159-70d7-9d81-4e0a06ba016f" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_019fd2c8-7159-73ae-82fd-ed3ec6f9bade" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019fd2c8-7159-7165-a7e3-5185dd560cdf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fd2c8-7159-70d7-9d81-4e0a06ba016f" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019fd2c8-7159-7165-a7e3-5185dd560cdf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_ImpactOfReorganizationTransactionsInShares_019fd2c8-7159-7001-913d-39ec995f51a9" xlink:href="glxy-20260630.xsd#glxy_ImpactOfReorganizationTransactionsInShares"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_ImpactOfReorganizationTransactions_019fd2c8-7159-7abf-8dda-96e8cce6d5d1" xlink:href="glxy-20260630.xsd#glxy_ImpactOfReorganizationTransactions"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_019fd2c8-7159-7dbc-91c8-17e38df0b465" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fd2c8-7159-70d7-9d81-4e0a06ba016f" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_019fd2c8-7159-7dbc-91c8-17e38df0b465" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationForfeited_019fd2c8-7159-7c75-ab42-b73ad0d6e37d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationForfeited"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fd2c8-7159-70d7-9d81-4e0a06ba016f" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationForfeited_019fd2c8-7159-7c75-ab42-b73ad0d6e37d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensationForfeited_019fd2c8-7159-74c6-a9c7-f6dba029dceb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensationForfeited"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fd2c8-7159-70d7-9d81-4e0a06ba016f" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensationForfeited_019fd2c8-7159-74c6-a9c7-f6dba029dceb" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_019fd2c8-7159-74fa-9653-52041d2429d0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fd2c8-7159-70d7-9d81-4e0a06ba016f" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_019fd2c8-7159-74fa-9653-52041d2429d0" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_019fd2c8-7159-7832-ada4-74e77877584b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fd2c8-7159-70d7-9d81-4e0a06ba016f" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_019fd2c8-7159-7832-ada4-74e77877584b" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_019fd2c8-7159-7711-b85c-f5b92211b833" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fd2c8-7159-70d7-9d81-4e0a06ba016f" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_019fd2c8-7159-7711-b85c-f5b92211b833" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_019fd2c8-7159-71f1-8b91-017e8f9f7a72" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fd2c8-7159-70d7-9d81-4e0a06ba016f" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_019fd2c8-7159-71f1-8b91-017e8f9f7a72" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityOther_019fd2c8-7159-7f1b-9c8e-041cd3ef2f00" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fd2c8-7159-70d7-9d81-4e0a06ba016f" xlink:to="loc_us-gaap_StockholdersEquityOther_019fd2c8-7159-7f1b-9c8e-041cd3ef2f00" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_NetIncomeLossAttributableToParentPostReorganization_019fd2c8-7159-7d6b-89ce-7fe40254ca09" xlink:href="glxy-20260630.xsd#glxy_NetIncomeLossAttributableToParentPostReorganization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fd2c8-7159-70d7-9d81-4e0a06ba016f" xlink:to="loc_glxy_NetIncomeLossAttributableToParentPostReorganization_019fd2c8-7159-7d6b-89ce-7fe40254ca09" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019fd2c8-7159-7207-9a7a-cc5624576b4c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019fd2c8-7159-70d7-9d81-4e0a06ba016f" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019fd2c8-7159-7207-9a7a-cc5624576b4c" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019fd2c8-7159-77f7-a352-12bbd5d85f7b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019fd2c8-7159-7662-8758-cd75f0efc0b5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/BUSINESSCOMBINATIONSNarrativeDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#BUSINESSCOMBINATIONSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/BUSINESSCOMBINATIONSNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-7159-77aa-9806-74dd87ad4837" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019fd2c8-7159-7110-a783-b6504b870fea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-7159-77aa-9806-74dd87ad4837" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019fd2c8-7159-7110-a783-b6504b870fea" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_019fd2c8-7159-7d7d-b4dd-352fb5216023" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019fd2c8-7159-7110-a783-b6504b870fea" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_019fd2c8-7159-7d7d-b4dd-352fb5216023" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019fd2c8-7159-7d7d-b4dd-352fb5216023_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019fd2c8-7159-7d7d-b4dd-352fb5216023" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019fd2c8-7159-7d7d-b4dd-352fb5216023_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019fd2c8-7159-70dc-b27e-14587751dc22" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019fd2c8-7159-7d7d-b4dd-352fb5216023" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019fd2c8-7159-70dc-b27e-14587751dc22" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_AlluvialFinanceMember_019fd2c8-7159-7dc9-a7df-7136c095507f" xlink:href="glxy-20260630.xsd#glxy_AlluvialFinanceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019fd2c8-7159-70dc-b27e-14587751dc22" xlink:to="loc_glxy_AlluvialFinanceMember_019fd2c8-7159-7dc9-a7df-7136c095507f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_MeridianLabsMember_019fd2c8-7159-76ea-ba26-07791edaf3f3" xlink:href="glxy-20260630.xsd#glxy_MeridianLabsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019fd2c8-7159-70dc-b27e-14587751dc22" xlink:to="loc_glxy_MeridianLabsMember_019fd2c8-7159-76ea-ba26-07791edaf3f3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_019fd2c8-7159-7da0-bd7e-c9917b24d3b6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-7159-77aa-9806-74dd87ad4837" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_019fd2c8-7159-7da0-bd7e-c9917b24d3b6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_019fd2c8-7159-74b2-9a5c-ce5730c8e2cf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-7159-77aa-9806-74dd87ad4837" xlink:to="loc_us-gaap_Goodwill_019fd2c8-7159-74b2-9a5c-ce5730c8e2cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_019fd2c8-7159-707f-bc8b-d40ce026f3e4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-7159-77aa-9806-74dd87ad4837" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_019fd2c8-7159-707f-bc8b-d40ce026f3e4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionCostOfAcquiredEntityTransactionCosts_019fd2c8-7159-76ad-a4ff-9eaa4db22b1f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionCostOfAcquiredEntityTransactionCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-7159-77aa-9806-74dd87ad4837" xlink:to="loc_us-gaap_BusinessAcquisitionCostOfAcquiredEntityTransactionCosts_019fd2c8-7159-76ad-a4ff-9eaa4db22b1f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_019fd2c8-7159-7eb7-bab3-f6cfab2b67fc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationContingentConsiderationLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-7159-77aa-9806-74dd87ad4837" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_019fd2c8-7159-7eb7-bab3-f6cfab2b67fc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh_019fd2c8-7159-7b93-b2d6-3367110cac67" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-7159-77aa-9806-74dd87ad4837" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh_019fd2c8-7159-7b93-b2d6-3367110cac67" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/BUSINESSCOMBINATIONSScheduleofAssetsandLiabilitiesRecognizedinRelationtoAcquisitionDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#BUSINESSCOMBINATIONSScheduleofAssetsandLiabilitiesRecognizedinRelationtoAcquisitionDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/BUSINESSCOMBINATIONSScheduleofAssetsandLiabilitiesRecognizedinRelationtoAcquisitionDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-7159-726e-839f-835224fbdcda" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019fd2c8-7159-7a81-806f-6ab06983e58c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-7159-726e-839f-835224fbdcda" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019fd2c8-7159-7a81-806f-6ab06983e58c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_019fd2c8-7159-7611-a3d5-8830587c57c1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019fd2c8-7159-7a81-806f-6ab06983e58c" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_019fd2c8-7159-7611-a3d5-8830587c57c1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019fd2c8-7159-7611-a3d5-8830587c57c1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019fd2c8-7159-7611-a3d5-8830587c57c1" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019fd2c8-7159-7611-a3d5-8830587c57c1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019fd2c8-7159-7254-b6b5-47c4dde1b364" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019fd2c8-7159-7611-a3d5-8830587c57c1" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019fd2c8-7159-7254-b6b5-47c4dde1b364" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_AlluvialFinanceMember_019fd2c8-7159-78df-8e49-bbe2cd14568b" xlink:href="glxy-20260630.xsd#glxy_AlluvialFinanceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019fd2c8-7159-7254-b6b5-47c4dde1b364" xlink:to="loc_glxy_AlluvialFinanceMember_019fd2c8-7159-78df-8e49-bbe2cd14568b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_019fd2c8-7159-7b0b-bf6f-8f4d8df72066" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-7159-726e-839f-835224fbdcda" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_019fd2c8-7159-7b0b-bf6f-8f4d8df72066" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_BusinessCombinationRecognizedAssetAcquiredOtherAssets_019fd2c8-7159-7103-a9c1-5121ac8ceff4" xlink:href="glxy-20260630.xsd#glxy_BusinessCombinationRecognizedAssetAcquiredOtherAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-7159-726e-839f-835224fbdcda" xlink:to="loc_glxy_BusinessCombinationRecognizedAssetAcquiredOtherAssets_019fd2c8-7159-7103-a9c1-5121ac8ceff4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_019fd2c8-7159-74ab-81d8-b5062facebbe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-7159-726e-839f-835224fbdcda" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_019fd2c8-7159-74ab-81d8-b5062facebbe" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_019fd2c8-7159-7ebb-a22a-4049955302fe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-7159-726e-839f-835224fbdcda" xlink:to="loc_us-gaap_Goodwill_019fd2c8-7159-7ebb-a22a-4049955302fe" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAcquiredIncludingGoodwill_019fd2c8-7159-7e0c-954f-9c3e7951c177" xlink:href="glxy-20260630.xsd#glxy_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAcquiredIncludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-7159-726e-839f-835224fbdcda" xlink:to="loc_glxy_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAcquiredIncludingGoodwill_019fd2c8-7159-7e0c-954f-9c3e7951c177" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/DIGITALASSETSNarrativeDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#DIGITALASSETSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/DIGITALASSETSNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CryptoAssetActivityLineItems_019fd2c8-7159-7f55-874c-8f4f6ab3e122" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CryptoAssetActivityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CryptoAssetActivityTable_019fd2c8-7159-78a2-923f-ee8d8bacea12" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CryptoAssetActivityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CryptoAssetActivityLineItems_019fd2c8-7159-7f55-874c-8f4f6ab3e122" xlink:to="loc_us-gaap_CryptoAssetActivityTable_019fd2c8-7159-78a2-923f-ee8d8bacea12" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CryptoAssetAxis_019fd2c8-7159-7a54-959c-4d0dccbd87e2" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CryptoAssetAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CryptoAssetActivityTable_019fd2c8-7159-78a2-923f-ee8d8bacea12" xlink:to="loc_srt_CryptoAssetAxis_019fd2c8-7159-7a54-959c-4d0dccbd87e2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CryptoAssetDomain_019fd2c8-7159-7a54-959c-4d0dccbd87e2_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CryptoAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CryptoAssetAxis_019fd2c8-7159-7a54-959c-4d0dccbd87e2" xlink:to="loc_srt_CryptoAssetDomain_019fd2c8-7159-7a54-959c-4d0dccbd87e2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CryptoAssetDomain_019fd2c8-7159-702b-b416-3e74f99ffef5" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CryptoAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CryptoAssetAxis_019fd2c8-7159-7a54-959c-4d0dccbd87e2" xlink:to="loc_srt_CryptoAssetDomain_019fd2c8-7159-702b-b416-3e74f99ffef5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_RestrictedByLockUpSchedulesMember_019fd2c8-7159-7a6d-9bbc-e351aa908ffd" xlink:href="glxy-20260630.xsd#glxy_RestrictedByLockUpSchedulesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CryptoAssetDomain_019fd2c8-7159-702b-b416-3e74f99ffef5" xlink:to="loc_glxy_RestrictedByLockUpSchedulesMember_019fd2c8-7159-7a6d-9bbc-e351aa908ffd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DigitalAssetsStakedMember_019fd2c8-7159-7533-a2aa-160ec10f442f" xlink:href="glxy-20260630.xsd#glxy_DigitalAssetsStakedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CryptoAssetDomain_019fd2c8-7159-702b-b416-3e74f99ffef5" xlink:to="loc_glxy_DigitalAssetsStakedMember_019fd2c8-7159-7533-a2aa-160ec10f442f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019fd2c8-7159-7809-a882-8706deb9cabd" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CryptoAssetActivityTable_019fd2c8-7159-78a2-923f-ee8d8bacea12" xlink:to="loc_srt_RangeAxis_019fd2c8-7159-7809-a882-8706deb9cabd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fd2c8-7159-7809-a882-8706deb9cabd_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019fd2c8-7159-7809-a882-8706deb9cabd" xlink:to="loc_srt_RangeMember_019fd2c8-7159-7809-a882-8706deb9cabd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fd2c8-7159-7b8e-a11c-d9c61c8df290" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019fd2c8-7159-7809-a882-8706deb9cabd" xlink:to="loc_srt_RangeMember_019fd2c8-7159-7b8e-a11c-d9c61c8df290" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019fd2c8-7159-711b-a002-dfae4d1e4717" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019fd2c8-7159-7b8e-a11c-d9c61c8df290" xlink:to="loc_srt_MaximumMember_019fd2c8-7159-711b-a002-dfae4d1e4717" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetFairValueAndCost_019fd2c8-7159-7527-82f1-bfb9eb5342be" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetFairValueAndCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CryptoAssetActivityLineItems_019fd2c8-7159-7f55-874c-8f4f6ab3e122" xlink:to="loc_glxy_CryptoAssetFairValueAndCost_019fd2c8-7159-7527-82f1-bfb9eb5342be" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CryptoAssetRealizedGainLossOperating_019fd2c8-7159-75dc-b3f9-50684a9e9289" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CryptoAssetRealizedGainLossOperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CryptoAssetActivityLineItems_019fd2c8-7159-7f55-874c-8f4f6ab3e122" xlink:to="loc_us-gaap_CryptoAssetRealizedGainLossOperating_019fd2c8-7159-75dc-b3f9-50684a9e9289" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CryptoAssetFairValueRestricted_019fd2c8-7159-7b69-b8ca-d74f91f86ad8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CryptoAssetFairValueRestricted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CryptoAssetActivityLineItems_019fd2c8-7159-7f55-874c-8f4f6ab3e122" xlink:to="loc_us-gaap_CryptoAssetFairValueRestricted_019fd2c8-7159-7b69-b8ca-d74f91f86ad8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetFairValueRestrictedDuration_019fd2c8-7159-78c0-a87d-9508042babfe" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetFairValueRestrictedDuration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CryptoAssetActivityLineItems_019fd2c8-7159-7f55-874c-8f4f6ab3e122" xlink:to="loc_glxy_CryptoAssetFairValueRestrictedDuration_019fd2c8-7159-78c0-a87d-9508042babfe" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/DIGITALASSETSScheduleofAdditionalDetailRelatedtotheDigitalAssetsDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#DIGITALASSETSScheduleofAdditionalDetailRelatedtotheDigitalAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/DIGITALASSETSScheduleofAdditionalDetailRelatedtotheDigitalAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CryptoAssetHoldingLineItems_019fd2c8-7159-7ae6-b242-bb52dd24a783" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CryptoAssetHoldingLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CryptoAssetHoldingTable_019fd2c8-7159-7f12-9b8c-9c81fd5072da" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CryptoAssetHoldingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CryptoAssetHoldingLineItems_019fd2c8-7159-7ae6-b242-bb52dd24a783" xlink:to="loc_us-gaap_CryptoAssetHoldingTable_019fd2c8-7159-7f12-9b8c-9c81fd5072da" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CryptoAssetAxis_019fd2c8-7159-7d79-97e5-60865be5ab93" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CryptoAssetAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CryptoAssetHoldingTable_019fd2c8-7159-7f12-9b8c-9c81fd5072da" xlink:to="loc_srt_CryptoAssetAxis_019fd2c8-7159-7d79-97e5-60865be5ab93" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CryptoAssetDomain_019fd2c8-7159-7d79-97e5-60865be5ab93_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CryptoAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CryptoAssetAxis_019fd2c8-7159-7d79-97e5-60865be5ab93" xlink:to="loc_srt_CryptoAssetDomain_019fd2c8-7159-7d79-97e5-60865be5ab93_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CryptoAssetDomain_019fd2c8-7159-7c50-9967-85d591c042e5" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CryptoAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CryptoAssetAxis_019fd2c8-7159-7d79-97e5-60865be5ab93" xlink:to="loc_srt_CryptoAssetDomain_019fd2c8-7159-7c50-9967-85d591c042e5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetSelfCustodiedMember_019fd2c8-7159-71d4-a67a-af34c774738a" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetSelfCustodiedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CryptoAssetDomain_019fd2c8-7159-7c50-9967-85d591c042e5" xlink:to="loc_glxy_CryptoAssetSelfCustodiedMember_019fd2c8-7159-71d4-a67a-af34c774738a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetHeldWithThirdPartiesMember_019fd2c8-7159-757d-8f1d-c65c520d0118" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetHeldWithThirdPartiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CryptoAssetDomain_019fd2c8-7159-7c50-9967-85d591c042e5" xlink:to="loc_glxy_CryptoAssetHeldWithThirdPartiesMember_019fd2c8-7159-757d-8f1d-c65c520d0118" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetCollateralPostedWithCounterpartiesMember_019fd2c8-7159-778e-9af1-30aaac6c8f27" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetCollateralPostedWithCounterpartiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CryptoAssetDomain_019fd2c8-7159-7c50-9967-85d591c042e5" xlink:to="loc_glxy_CryptoAssetCollateralPostedWithCounterpartiesMember_019fd2c8-7159-778e-9af1-30aaac6c8f27" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetDecentralizedFinanceProtocolsMember_019fd2c8-7159-7392-86f5-ada0188caec1" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetDecentralizedFinanceProtocolsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CryptoAssetDomain_019fd2c8-7159-7c50-9967-85d591c042e5" xlink:to="loc_glxy_CryptoAssetDecentralizedFinanceProtocolsMember_019fd2c8-7159-7392-86f5-ada0188caec1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetIntangibleAssetsCurrentFairValue_019fd2c8-7159-779d-8891-3dc271b7094d" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetIntangibleAssetsCurrentFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CryptoAssetHoldingLineItems_019fd2c8-7159-7ae6-b242-bb52dd24a783" xlink:to="loc_glxy_CryptoAssetIntangibleAssetsCurrentFairValue_019fd2c8-7159-779d-8891-3dc271b7094d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetIntangibleAssetsCurrent_019fd2c8-7159-7cf9-ba97-7f1e78a22698" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetIntangibleAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CryptoAssetHoldingLineItems_019fd2c8-7159-7ae6-b242-bb52dd24a783" xlink:to="loc_glxy_CryptoAssetIntangibleAssetsCurrent_019fd2c8-7159-7cf9-ba97-7f1e78a22698" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetFinancialAssetCurrent_019fd2c8-7159-7e53-b94d-512d4a5f1977" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetFinancialAssetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CryptoAssetHoldingLineItems_019fd2c8-7159-7ae6-b242-bb52dd24a783" xlink:to="loc_glxy_CryptoAssetFinancialAssetCurrent_019fd2c8-7159-7e53-b94d-512d4a5f1977" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetIntangibleAssetNoncurrent_019fd2c8-7159-7d5c-aea8-c4d2eb67fad9" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetIntangibleAssetNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CryptoAssetHoldingLineItems_019fd2c8-7159-7ae6-b242-bb52dd24a783" xlink:to="loc_glxy_CryptoAssetIntangibleAssetNoncurrent_019fd2c8-7159-7d5c-aea8-c4d2eb67fad9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetIntangibleAssets_019fd2c8-7159-7b18-bfb4-2e00610fb086" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CryptoAssetHoldingLineItems_019fd2c8-7159-7ae6-b242-bb52dd24a783" xlink:to="loc_glxy_CryptoAssetIntangibleAssets_019fd2c8-7159-7b18-bfb4-2e00610fb086" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetFinancialAsset_019fd2c8-7159-7d4d-842c-e1e6548cf48e" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetFinancialAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CryptoAssetHoldingLineItems_019fd2c8-7159-7ae6-b242-bb52dd24a783" xlink:to="loc_glxy_CryptoAssetFinancialAsset_019fd2c8-7159-7d4d-842c-e1e6548cf48e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetFairValueAndCost_019fd2c8-7159-7543-b2b0-b9cd6181e75e" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetFairValueAndCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CryptoAssetHoldingLineItems_019fd2c8-7159-7ae6-b242-bb52dd24a783" xlink:to="loc_glxy_CryptoAssetFairValueAndCost_019fd2c8-7159-7543-b2b0-b9cd6181e75e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetCollateralPostedWithCounterpartiesDigitalAssetAndFiatBorrowings_019fd2c8-7159-7362-9d39-fffe0a0beb73" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetCollateralPostedWithCounterpartiesDigitalAssetAndFiatBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CryptoAssetHoldingLineItems_019fd2c8-7159-7ae6-b242-bb52dd24a783" xlink:to="loc_glxy_CryptoAssetCollateralPostedWithCounterpartiesDigitalAssetAndFiatBorrowings_019fd2c8-7159-7362-9d39-fffe0a0beb73" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetAssociatedWithDecentralizedFinanceProtocolsSupportsBorrowings_019fd2c8-7159-755b-8da4-8e88ecb0c1d9" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetAssociatedWithDecentralizedFinanceProtocolsSupportsBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CryptoAssetHoldingLineItems_019fd2c8-7159-7ae6-b242-bb52dd24a783" xlink:to="loc_glxy_CryptoAssetAssociatedWithDecentralizedFinanceProtocolsSupportsBorrowings_019fd2c8-7159-755b-8da4-8e88ecb0c1d9" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DebtInstrumentCovenantLoanToValueRatio_019fd2c8-7159-7a8c-8fbc-81193f63cb24" xlink:href="glxy-20260630.xsd#glxy_DebtInstrumentCovenantLoanToValueRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CryptoAssetHoldingLineItems_019fd2c8-7159-7ae6-b242-bb52dd24a783" xlink:to="loc_glxy_DebtInstrumentCovenantLoanToValueRatio_019fd2c8-7159-7a8c-8fbc-81193f63cb24" xlink:type="arc" order="9"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/DIGITALASSETSScheduleofGrossDigitalAssetHoldingsDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#DIGITALASSETSScheduleofGrossDigitalAssetHoldingsDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/DIGITALASSETSScheduleofGrossDigitalAssetHoldingsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CryptoAssetHoldingLineItems_019fd2c8-7159-7ae8-ac95-5257d9f3eef4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CryptoAssetHoldingLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CryptoAssetHoldingTable_019fd2c8-7159-7592-b4d7-fe3ddc2d2965" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CryptoAssetHoldingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CryptoAssetHoldingLineItems_019fd2c8-7159-7ae8-ac95-5257d9f3eef4" xlink:to="loc_us-gaap_CryptoAssetHoldingTable_019fd2c8-7159-7592-b4d7-fe3ddc2d2965" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CryptoAssetAxis_019fd2c8-7159-79c7-a64d-95f888e2c2a9" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CryptoAssetAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CryptoAssetHoldingTable_019fd2c8-7159-7592-b4d7-fe3ddc2d2965" xlink:to="loc_srt_CryptoAssetAxis_019fd2c8-7159-79c7-a64d-95f888e2c2a9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CryptoAssetDomain_019fd2c8-7159-79c7-a64d-95f888e2c2a9_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CryptoAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CryptoAssetAxis_019fd2c8-7159-79c7-a64d-95f888e2c2a9" xlink:to="loc_srt_CryptoAssetDomain_019fd2c8-7159-79c7-a64d-95f888e2c2a9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CryptoAssetDomain_019fd2c8-7159-7815-a844-62a97564cd44" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CryptoAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CryptoAssetAxis_019fd2c8-7159-79c7-a64d-95f888e2c2a9" xlink:to="loc_srt_CryptoAssetDomain_019fd2c8-7159-7815-a844-62a97564cd44" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_BitcoinMember_019fd2c8-7159-7679-be24-6c215d767a58" xlink:href="glxy-20260630.xsd#glxy_BitcoinMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CryptoAssetDomain_019fd2c8-7159-7815-a844-62a97564cd44" xlink:to="loc_glxy_BitcoinMember_019fd2c8-7159-7679-be24-6c215d767a58" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_USDCMember_019fd2c8-7159-71ac-8b03-f9d474c6082d" xlink:href="glxy-20260630.xsd#glxy_USDCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CryptoAssetDomain_019fd2c8-7159-7815-a844-62a97564cd44" xlink:to="loc_glxy_USDCMember_019fd2c8-7159-71ac-8b03-f9d474c6082d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_EtherMember_019fd2c8-7159-77af-84bd-1ee6535ca76b" xlink:href="glxy-20260630.xsd#glxy_EtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CryptoAssetDomain_019fd2c8-7159-7815-a844-62a97564cd44" xlink:to="loc_glxy_EtherMember_019fd2c8-7159-77af-84bd-1ee6535ca76b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_SWEEPMember_019fd2c8-7159-79e8-ac20-5bde9bf672b5" xlink:href="glxy-20260630.xsd#glxy_SWEEPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CryptoAssetDomain_019fd2c8-7159-7815-a844-62a97564cd44" xlink:to="loc_glxy_SWEEPMember_019fd2c8-7159-79e8-ac20-5bde9bf672b5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_HYPEMember_019fd2c8-7159-79c4-9f11-cb6a322c0043" xlink:href="glxy-20260630.xsd#glxy_HYPEMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CryptoAssetDomain_019fd2c8-7159-7815-a844-62a97564cd44" xlink:to="loc_glxy_HYPEMember_019fd2c8-7159-79c4-9f11-cb6a322c0043" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_SOLMember_019fd2c8-7159-718c-b2f9-f260c5018173" xlink:href="glxy-20260630.xsd#glxy_SOLMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CryptoAssetDomain_019fd2c8-7159-7815-a844-62a97564cd44" xlink:to="loc_glxy_SOLMember_019fd2c8-7159-718c-b2f9-f260c5018173" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_KVPYUSDMember_019fd2c8-7159-7e34-bd3a-b261e012b5e2" xlink:href="glxy-20260630.xsd#glxy_KVPYUSDMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CryptoAssetDomain_019fd2c8-7159-7815-a844-62a97564cd44" xlink:to="loc_glxy_KVPYUSDMember_019fd2c8-7159-7e34-bd3a-b261e012b5e2" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CryptoAssetOtherMember_019fd2c8-7159-7739-aea2-abde6246605b" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CryptoAssetOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CryptoAssetDomain_019fd2c8-7159-7815-a844-62a97564cd44" xlink:to="loc_srt_CryptoAssetOtherMember_019fd2c8-7159-7739-aea2-abde6246605b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_AETHUSDCMember_019fd2c8-7159-7a72-a8ed-305108c835a0" xlink:href="glxy-20260630.xsd#glxy_AETHUSDCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CryptoAssetDomain_019fd2c8-7159-7815-a844-62a97564cd44" xlink:to="loc_glxy_AETHUSDCMember_019fd2c8-7159-7a72-a8ed-305108c835a0" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_SUSDCMember_019fd2c8-7159-7a72-8156-9b4d470fab30" xlink:href="glxy-20260630.xsd#glxy_SUSDCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CryptoAssetDomain_019fd2c8-7159-7815-a844-62a97564cd44" xlink:to="loc_glxy_SUSDCMember_019fd2c8-7159-7a72-8156-9b4d470fab30" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_GTSYMember_019fd2c8-7159-7359-a65f-7c3e9aea7345" xlink:href="glxy-20260630.xsd#glxy_GTSYMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CryptoAssetDomain_019fd2c8-7159-7815-a844-62a97564cd44" xlink:to="loc_glxy_GTSYMember_019fd2c8-7159-7359-a65f-7c3e9aea7345" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_019fd2c8-7159-7e51-b203-5c763ebab7fe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CryptoAssetHoldingTable_019fd2c8-7159-7592-b4d7-fe3ddc2d2965" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_019fd2c8-7159-7e51-b203-5c763ebab7fe" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019fd2c8-7159-7e51-b203-5c763ebab7fe_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_019fd2c8-7159-7e51-b203-5c763ebab7fe" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019fd2c8-7159-7e51-b203-5c763ebab7fe_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019fd2c8-7159-7708-b25c-fdeb1f6c325b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_019fd2c8-7159-7e51-b203-5c763ebab7fe" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019fd2c8-7159-7708-b25c-fdeb1f6c325b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019fd2c8-7159-7394-b867-a63883f13056" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019fd2c8-7159-7708-b25c-fdeb1f6c325b" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019fd2c8-7159-7394-b867-a63883f13056" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_019fd2c8-7159-772b-94c6-851afacd2713" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019fd2c8-7159-7394-b867-a63883f13056" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_019fd2c8-7159-772b-94c6-851afacd2713" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtOtherThanFairValueFairValueDisclosureMember_019fd2c8-7159-73d8-a273-087601a680f5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PortionAtOtherThanFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019fd2c8-7159-7708-b25c-fdeb1f6c325b" xlink:to="loc_us-gaap_PortionAtOtherThanFairValueFairValueDisclosureMember_019fd2c8-7159-73d8-a273-087601a680f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CryptoAssetNumberOfUnits_019fd2c8-7159-7d2b-b7a1-7697b1c8e340" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CryptoAssetNumberOfUnits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CryptoAssetHoldingLineItems_019fd2c8-7159-7ae8-ac95-5257d9f3eef4" xlink:to="loc_us-gaap_CryptoAssetNumberOfUnits_019fd2c8-7159-7d2b-b7a1-7697b1c8e340" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CryptoAssetCost_019fd2c8-7159-7bee-98d6-71595ace2f12" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CryptoAssetCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CryptoAssetHoldingLineItems_019fd2c8-7159-7ae8-ac95-5257d9f3eef4" xlink:to="loc_us-gaap_CryptoAssetCost_019fd2c8-7159-7bee-98d6-71595ace2f12" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CryptoAssetFairValue_019fd2c8-7159-77fd-b1f5-fa9a2fc66faf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CryptoAssetFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CryptoAssetHoldingLineItems_019fd2c8-7159-7ae8-ac95-5257d9f3eef4" xlink:to="loc_us-gaap_CryptoAssetFairValue_019fd2c8-7159-77fd-b1f5-fa9a2fc66faf" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/DIGITALASSETLOANSRECEIVABLEANDDIGITALASSETSBORROWEDScheduleofDigitalAssetsLoanReceivableNetofAllowanceDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#DIGITALASSETLOANSRECEIVABLEANDDIGITALASSETSBORROWEDScheduleofDigitalAssetsLoanReceivableNetofAllowanceDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/DIGITALASSETLOANSRECEIVABLEANDDIGITALASSETSBORROWEDScheduleofDigitalAssetsLoanReceivableNetofAllowanceDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fd2c8-7159-75e8-ad06-5ec1aae71fdd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fd2c8-7159-7258-84bf-25fe7f70bde2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fd2c8-7159-75e8-ad06-5ec1aae71fdd" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fd2c8-7159-7258-84bf-25fe7f70bde2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019fd2c8-7159-71a5-9caf-b2629c3a8b47" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fd2c8-7159-7258-84bf-25fe7f70bde2" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019fd2c8-7159-71a5-9caf-b2629c3a8b47" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_019fd2c8-7159-71a5-9caf-b2629c3a8b47_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019fd2c8-7159-71a5-9caf-b2629c3a8b47" xlink:to="loc_us-gaap_ReceivableTypeDomain_019fd2c8-7159-71a5-9caf-b2629c3a8b47_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_019fd2c8-7159-7528-9530-e832b43d657d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019fd2c8-7159-71a5-9caf-b2629c3a8b47" xlink:to="loc_us-gaap_ReceivableTypeDomain_019fd2c8-7159-7528-9530-e832b43d657d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetsLoansReceivableMember_019fd2c8-7159-7987-8642-be5248215439" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetsLoansReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivableTypeDomain_019fd2c8-7159-7528-9530-e832b43d657d" xlink:to="loc_glxy_CryptoAssetsLoansReceivableMember_019fd2c8-7159-7987-8642-be5248215439" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesReceivableGross_019fd2c8-7159-7376-aae8-ce0e6041df2e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesReceivableGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fd2c8-7159-75e8-ad06-5ec1aae71fdd" xlink:to="loc_us-gaap_NotesReceivableGross_019fd2c8-7159-7376-aae8-ce0e6041df2e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermAccountsNotesAndLoansReceivableNetNoncurrent_019fd2c8-7159-75fb-8a96-9abb496bdf0a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermAccountsNotesAndLoansReceivableNetNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fd2c8-7159-75e8-ad06-5ec1aae71fdd" xlink:to="loc_us-gaap_LongTermAccountsNotesAndLoansReceivableNetNoncurrent_019fd2c8-7159-75fb-8a96-9abb496bdf0a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_019fd2c8-7159-7743-96dc-a4e9bd80a543" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLosses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fd2c8-7159-75e8-ad06-5ec1aae71fdd" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_019fd2c8-7159-7743-96dc-a4e9bd80a543" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesReceivableNet_019fd2c8-7159-7251-b77e-f0f45379febd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesReceivableNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fd2c8-7159-75e8-ad06-5ec1aae71fdd" xlink:to="loc_us-gaap_NotesReceivableNet_019fd2c8-7159-7251-b77e-f0f45379febd" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/DIGITALASSETLOANSRECEIVABLEANDDIGITALASSETSBORROWEDScheduleofCollateralPayableAssociatedwithDigitalAssetsLoansReceivableDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#DIGITALASSETLOANSRECEIVABLEANDDIGITALASSETSBORROWEDScheduleofCollateralPayableAssociatedwithDigitalAssetsLoansReceivableDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/DIGITALASSETLOANSRECEIVABLEANDDIGITALASSETSBORROWEDScheduleofCollateralPayableAssociatedwithDigitalAssetsLoansReceivableDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fd2c8-7159-78a5-8a5c-889ed5d50fb7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fd2c8-7159-70ab-bc4c-432eeeaeb05b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fd2c8-7159-78a5-8a5c-889ed5d50fb7" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fd2c8-7159-70ab-bc4c-432eeeaeb05b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7159-7be6-a5fb-92225fd2351e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByAssetClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fd2c8-7159-70ab-bc4c-432eeeaeb05b" xlink:to="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7159-7be6-a5fb-92225fd2351e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7159-7be6-a5fb-92225fd2351e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7159-7be6-a5fb-92225fd2351e" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7159-7be6-a5fb-92225fd2351e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7159-785b-a5f5-a03e8d5c6670" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7159-7be6-a5fb-92225fd2351e" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7159-785b-a5f5-a03e8d5c6670" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DigitalAssetsMember_019fd2c8-7159-7d41-a6c0-ea17704e4e52" xlink:href="glxy-20260630.xsd#glxy_DigitalAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7159-785b-a5f5-a03e8d5c6670" xlink:to="loc_glxy_DigitalAssetsMember_019fd2c8-7159-7d41-a6c0-ea17704e4e52" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashMember_019fd2c8-7159-7792-a6b5-e9eb962af4d0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7159-785b-a5f5-a03e8d5c6670" xlink:to="loc_us-gaap_CashMember_019fd2c8-7159-7792-a6b5-e9eb962af4d0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_FinancingReceivableAllowanceForCreditLossCollateralPayable_019fd2c8-7159-7785-96cc-26a3449b39d4" xlink:href="glxy-20260630.xsd#glxy_FinancingReceivableAllowanceForCreditLossCollateralPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fd2c8-7159-78a5-8a5c-889ed5d50fb7" xlink:to="loc_glxy_FinancingReceivableAllowanceForCreditLossCollateralPayable_019fd2c8-7159-7785-96cc-26a3449b39d4" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/DIGITALASSETLOANSRECEIVABLEANDDIGITALASSETSBORROWEDNarrativeDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#DIGITALASSETLOANSRECEIVABLEANDDIGITALASSETSBORROWEDNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/DIGITALASSETLOANSRECEIVABLEANDDIGITALASSETSBORROWEDNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fd2c8-7159-7dbd-bae7-3422011cb4f8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fd2c8-7159-7ca1-9747-61d2a6dc9abe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fd2c8-7159-7dbd-bae7-3422011cb4f8" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fd2c8-7159-7ca1-9747-61d2a6dc9abe" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CryptoAssetAxis_019fd2c8-7159-78c3-a917-7cbcde759b01" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CryptoAssetAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fd2c8-7159-7ca1-9747-61d2a6dc9abe" xlink:to="loc_srt_CryptoAssetAxis_019fd2c8-7159-78c3-a917-7cbcde759b01" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CryptoAssetDomain_019fd2c8-7159-78c3-a917-7cbcde759b01_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CryptoAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CryptoAssetAxis_019fd2c8-7159-78c3-a917-7cbcde759b01" xlink:to="loc_srt_CryptoAssetDomain_019fd2c8-7159-78c3-a917-7cbcde759b01_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CryptoAssetDomain_019fd2c8-7159-70b0-9741-7a0e518351ce" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CryptoAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CryptoAssetAxis_019fd2c8-7159-78c3-a917-7cbcde759b01" xlink:to="loc_srt_CryptoAssetDomain_019fd2c8-7159-70b0-9741-7a0e518351ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_USDCBitcoinEtherPYUSDAndTetherMember_019fd2c8-7159-7b21-b29e-cbad3cf2deb0" xlink:href="glxy-20260630.xsd#glxy_USDCBitcoinEtherPYUSDAndTetherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CryptoAssetDomain_019fd2c8-7159-70b0-9741-7a0e518351ce" xlink:to="loc_glxy_USDCBitcoinEtherPYUSDAndTetherMember_019fd2c8-7159-7b21-b29e-cbad3cf2deb0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_BitcoinUSDCEtherTetherAndSOLMember_019fd2c8-7159-7597-8586-c0025388311f" xlink:href="glxy-20260630.xsd#glxy_BitcoinUSDCEtherTetherAndSOLMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CryptoAssetDomain_019fd2c8-7159-70b0-9741-7a0e518351ce" xlink:to="loc_glxy_BitcoinUSDCEtherTetherAndSOLMember_019fd2c8-7159-7597-8586-c0025388311f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetsBorrowedPercentage_019fd2c8-7159-799e-912a-f67e5574db46" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetsBorrowedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fd2c8-7159-7dbd-bae7-3422011cb4f8" xlink:to="loc_glxy_CryptoAssetsBorrowedPercentage_019fd2c8-7159-799e-912a-f67e5574db46" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/DIGITALASSETLOANSRECEIVABLEANDDIGITALASSETSBORROWEDScheduleofAssetsPostedasCollateralAssociatedwithDigitalAssetsBorrowedDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#DIGITALASSETLOANSRECEIVABLEANDDIGITALASSETSBORROWEDScheduleofAssetsPostedasCollateralAssociatedwithDigitalAssetsBorrowedDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/DIGITALASSETLOANSRECEIVABLEANDDIGITALASSETSBORROWEDScheduleofAssetsPostedasCollateralAssociatedwithDigitalAssetsBorrowedDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fd2c8-7159-7597-be80-2ba6d83ae1ec" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fd2c8-7159-7b55-b1fc-224b68fff860" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fd2c8-7159-7597-be80-2ba6d83ae1ec" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fd2c8-7159-7b55-b1fc-224b68fff860" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7159-7c52-8d5e-e1ab5d2447e7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByAssetClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fd2c8-7159-7b55-b1fc-224b68fff860" xlink:to="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7159-7c52-8d5e-e1ab5d2447e7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7159-7c52-8d5e-e1ab5d2447e7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7159-7c52-8d5e-e1ab5d2447e7" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7159-7c52-8d5e-e1ab5d2447e7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7159-715f-b563-43ee4b839db8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7159-7c52-8d5e-e1ab5d2447e7" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7159-715f-b563-43ee4b839db8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DigitalIntangibleAssetsMember_019fd2c8-7159-7745-8b2e-cc08f524ed4d" xlink:href="glxy-20260630.xsd#glxy_DigitalIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7159-715f-b563-43ee4b839db8" xlink:to="loc_glxy_DigitalIntangibleAssetsMember_019fd2c8-7159-7745-8b2e-cc08f524ed4d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_FinancingReceivableBeforeAllowanceForCreditLossDigitalAssetsPostedAsCollateral_019fd2c8-7159-7233-91d3-6a0177ae3850" xlink:href="glxy-20260630.xsd#glxy_FinancingReceivableBeforeAllowanceForCreditLossDigitalAssetsPostedAsCollateral"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fd2c8-7159-7597-be80-2ba6d83ae1ec" xlink:to="loc_glxy_FinancingReceivableBeforeAllowanceForCreditLossDigitalAssetsPostedAsCollateral_019fd2c8-7159-7233-91d3-6a0177ae3850" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_FinancingReceivableAllowanceForCreditLossDigitalAssetsPostedAsCollateral_019fd2c8-7159-721a-827f-8aa570265729" xlink:href="glxy-20260630.xsd#glxy_FinancingReceivableAllowanceForCreditLossDigitalAssetsPostedAsCollateral"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fd2c8-7159-7597-be80-2ba6d83ae1ec" xlink:to="loc_glxy_FinancingReceivableAllowanceForCreditLossDigitalAssetsPostedAsCollateral_019fd2c8-7159-721a-827f-8aa570265729" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_FinancingReceivableAfterAllowanceForCreditLossDigitalAssetsPostedAsCollateral_019fd2c8-7159-7935-9b45-88863b0427a6" xlink:href="glxy-20260630.xsd#glxy_FinancingReceivableAfterAllowanceForCreditLossDigitalAssetsPostedAsCollateral"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fd2c8-7159-7597-be80-2ba6d83ae1ec" xlink:to="loc_glxy_FinancingReceivableAfterAllowanceForCreditLossDigitalAssetsPostedAsCollateral_019fd2c8-7159-7935-9b45-88863b0427a6" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/DERIVATIVESScheduleofCompanysDerivativesPortfolioDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#DERIVATIVESScheduleofCompanysDerivativesPortfolioDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/DERIVATIVESScheduleofCompanysDerivativesPortfolioDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_019fd2c8-7159-7f7a-9af6-a5adca0bd781" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_019fd2c8-7159-75cf-a79b-9c009f865a8b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_019fd2c8-7159-7f7a-9af6-a5adca0bd781" xlink:to="loc_us-gaap_DerivativeTable_019fd2c8-7159-75cf-a79b-9c009f865a8b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_019fd2c8-7159-769a-8ba8-f229893d5280" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_019fd2c8-7159-75cf-a79b-9c009f865a8b" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_019fd2c8-7159-769a-8ba8-f229893d5280" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019fd2c8-7159-769a-8ba8-f229893d5280_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019fd2c8-7159-769a-8ba8-f229893d5280" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019fd2c8-7159-769a-8ba8-f229893d5280_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019fd2c8-7159-7cc0-becd-f393f6d16e44" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019fd2c8-7159-769a-8ba8-f229893d5280" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019fd2c8-7159-7cc0-becd-f393f6d16e44" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DigitalAssetsMember_019fd2c8-7159-71ea-ac96-a0dd1ca41a50" xlink:href="glxy-20260630.xsd#glxy_DigitalAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019fd2c8-7159-7cc0-becd-f393f6d16e44" xlink:to="loc_glxy_DigitalAssetsMember_019fd2c8-7159-71ea-ac96-a0dd1ca41a50" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeContractMember_019fd2c8-7159-7d82-a27b-251d33cdc519" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ForeignExchangeContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019fd2c8-7159-7cc0-becd-f393f6d16e44" xlink:to="loc_us-gaap_ForeignExchangeContractMember_019fd2c8-7159-7d82-a27b-251d33cdc519" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityContractMember_019fd2c8-7159-7f02-bb70-ee077c209ae7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019fd2c8-7159-7cc0-becd-f393f6d16e44" xlink:to="loc_us-gaap_EquityContractMember_019fd2c8-7159-7f02-bb70-ee077c209ae7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateContractMember_019fd2c8-7159-7f60-86d4-6461b88a972a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019fd2c8-7159-7cc0-becd-f393f6d16e44" xlink:to="loc_us-gaap_InterestRateContractMember_019fd2c8-7159-7f60-86d4-6461b88a972a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_019fd2c8-7159-7255-9759-0c04de20ad7c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019fd2c8-7159-7cc0-becd-f393f6d16e44" xlink:to="loc_us-gaap_CommodityContractMember_019fd2c8-7159-7255-9759-0c04de20ad7c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DigitalAssetsReceivableMember_019fd2c8-7159-7fda-b19f-ca146779ba3d" xlink:href="glxy-20260630.xsd#glxy_DigitalAssetsReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019fd2c8-7159-7cc0-becd-f393f6d16e44" xlink:to="loc_glxy_DigitalAssetsReceivableMember_019fd2c8-7159-7fda-b19f-ca146779ba3d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_EmbeddedDerivativeFinancialInstrumentsDigitalAssetsBorrowedMember_019fd2c8-7159-790a-bf1f-8664282f7393" xlink:href="glxy-20260630.xsd#glxy_EmbeddedDerivativeFinancialInstrumentsDigitalAssetsBorrowedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019fd2c8-7159-7cc0-becd-f393f6d16e44" xlink:to="loc_glxy_EmbeddedDerivativeFinancialInstrumentsDigitalAssetsBorrowedMember_019fd2c8-7159-790a-bf1f-8664282f7393" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_EmbeddedDerivativeFinancialInstrumentsCollateralPayableMember_019fd2c8-7159-7711-a603-dad05be5af18" xlink:href="glxy-20260630.xsd#glxy_EmbeddedDerivativeFinancialInstrumentsCollateralPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019fd2c8-7159-7cc0-becd-f393f6d16e44" xlink:to="loc_glxy_EmbeddedDerivativeFinancialInstrumentsCollateralPayableMember_019fd2c8-7159-7711-a603-dad05be5af18" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_EmbeddedDerivativeFinancialInstrumentsNotesPayableMember_019fd2c8-7159-76d4-bae0-3d1f664e9ddb" xlink:href="glxy-20260630.xsd#glxy_EmbeddedDerivativeFinancialInstrumentsNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019fd2c8-7159-7cc0-becd-f393f6d16e44" xlink:to="loc_glxy_EmbeddedDerivativeFinancialInstrumentsNotesPayableMember_019fd2c8-7159-76d4-bae0-3d1f664e9ddb" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_019fd2c8-7159-7f64-934d-9500742d63c7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019fd2c8-7159-7f7a-9af6-a5adca0bd781" xlink:to="loc_us-gaap_DerivativeNotionalAmount_019fd2c8-7159-7f64-934d-9500742d63c7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssets_019fd2c8-7159-7c94-bb23-39c2c4d12584" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019fd2c8-7159-7f7a-9af6-a5adca0bd781" xlink:to="loc_us-gaap_DerivativeAssets_019fd2c8-7159-7c94-bb23-39c2c4d12584" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilities_019fd2c8-7159-7ea3-94af-cd7199f8a8cd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019fd2c8-7159-7f7a-9af6-a5adca0bd781" xlink:to="loc_us-gaap_DerivativeLiabilities_019fd2c8-7159-7ea3-94af-cd7199f8a8cd" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/DERIVATIVESScheduleOfCollateralPayableAssociatedWithDerivativePositionsDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#DERIVATIVESScheduleOfCollateralPayableAssociatedWithDerivativePositionsDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/DERIVATIVESScheduleOfCollateralPayableAssociatedWithDerivativePositionsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_019fd2c8-7159-7fbd-a1ba-301346b450dc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_019fd2c8-7159-7722-9b68-78f90c3f9f9d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_019fd2c8-7159-7fbd-a1ba-301346b450dc" xlink:to="loc_us-gaap_DerivativeTable_019fd2c8-7159-7722-9b68-78f90c3f9f9d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7159-7abc-ae70-e480df07baec" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByAssetClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_019fd2c8-7159-7722-9b68-78f90c3f9f9d" xlink:to="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7159-7abc-ae70-e480df07baec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7159-7abc-ae70-e480df07baec_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7159-7abc-ae70-e480df07baec" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7159-7abc-ae70-e480df07baec_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7159-79a8-bfdb-2bd05bba8abb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7159-7abc-ae70-e480df07baec" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7159-79a8-bfdb-2bd05bba8abb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DigitalAssestsMember_019fd2c8-7159-7384-bc9e-3e7617cb1680" xlink:href="glxy-20260630.xsd#glxy_DigitalAssestsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7159-79a8-bfdb-2bd05bba8abb" xlink:to="loc_glxy_DigitalAssestsMember_019fd2c8-7159-7384-bc9e-3e7617cb1680" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashMember_019fd2c8-7159-760a-8c20-5aa84ce7c643" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7159-79a8-bfdb-2bd05bba8abb" xlink:to="loc_us-gaap_CashMember_019fd2c8-7159-760a-8c20-5aa84ce7c643" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssetFairValueOfCollateral_019fd2c8-7159-7a43-9276-a0d58f278cd3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeAssetFairValueOfCollateral"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019fd2c8-7159-7fbd-a1ba-301346b450dc" xlink:to="loc_us-gaap_DerivativeAssetFairValueOfCollateral_019fd2c8-7159-7a43-9276-a0d58f278cd3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DerivativeAssetAssetsPostedAsCollateral_019fd2c8-7159-7b99-a79b-7801d693ba62" xlink:href="glxy-20260630.xsd#glxy_DerivativeAssetAssetsPostedAsCollateral"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019fd2c8-7159-7fbd-a1ba-301346b450dc" xlink:to="loc_glxy_DerivativeAssetAssetsPostedAsCollateral_019fd2c8-7159-7b99-a79b-7801d693ba62" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/DERIVATIVESScheduleofDerivativesDesignatedasHedgingInstrumentsDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#DERIVATIVESScheduleofDerivativesDesignatedasHedgingInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/DERIVATIVESScheduleofDerivativesDesignatedasHedgingInstrumentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_019fd2c8-7224-723f-86f3-a0ad546b6829" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_019fd2c8-7159-776c-93e4-5399eece2ca9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_019fd2c8-7224-723f-86f3-a0ad546b6829" xlink:to="loc_us-gaap_DerivativeTable_019fd2c8-7159-776c-93e4-5399eece2ca9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_019fd2c8-7159-7eee-a9e3-57d385068555" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_019fd2c8-7159-776c-93e4-5399eece2ca9" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_019fd2c8-7159-7eee-a9e3-57d385068555" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019fd2c8-7159-7eee-a9e3-57d385068555_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019fd2c8-7159-7eee-a9e3-57d385068555" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019fd2c8-7159-7eee-a9e3-57d385068555_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019fd2c8-7159-7158-b27f-590c25bc1c3b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019fd2c8-7159-7eee-a9e3-57d385068555" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019fd2c8-7159-7158-b27f-590c25bc1c3b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateContractMember_019fd2c8-7159-74f4-9cd8-11b29ff757c4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019fd2c8-7159-7158-b27f-590c25bc1c3b" xlink:to="loc_us-gaap_InterestRateContractMember_019fd2c8-7159-74f4-9cd8-11b29ff757c4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_019fd2c8-7159-7aba-8b62-793738110c49" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_019fd2c8-7159-776c-93e4-5399eece2ca9" xlink:to="loc_us-gaap_HedgingDesignationAxis_019fd2c8-7159-7aba-8b62-793738110c49" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019fd2c8-7159-7aba-8b62-793738110c49_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_019fd2c8-7159-7aba-8b62-793738110c49" xlink:to="loc_us-gaap_HedgingDesignationDomain_019fd2c8-7159-7aba-8b62-793738110c49_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019fd2c8-7159-7503-b8bc-7b98d07f857b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_019fd2c8-7159-7aba-8b62-793738110c49" xlink:to="loc_us-gaap_HedgingDesignationDomain_019fd2c8-7159-7503-b8bc-7b98d07f857b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_019fd2c8-7159-7655-b74d-a3c85596f6ed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_019fd2c8-7159-7503-b8bc-7b98d07f857b" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_019fd2c8-7159-7655-b74d-a3c85596f6ed" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019fd2c8-7159-7293-b1f3-5642c617e479" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_019fd2c8-7159-776c-93e4-5399eece2ca9" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019fd2c8-7159-7293-b1f3-5642c617e479" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_019fd2c8-7159-7293-b1f3-5642c617e479_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019fd2c8-7159-7293-b1f3-5642c617e479" xlink:to="loc_us-gaap_HedgingRelationshipDomain_019fd2c8-7159-7293-b1f3-5642c617e479_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_019fd2c8-7159-7128-aab2-3cda9193a03e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019fd2c8-7159-7293-b1f3-5642c617e479" xlink:to="loc_us-gaap_HedgingRelationshipDomain_019fd2c8-7159-7128-aab2-3cda9193a03e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgingMember_019fd2c8-7159-7c96-8501-3fff13dbbefb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashFlowHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_019fd2c8-7159-7128-aab2-3cda9193a03e" xlink:to="loc_us-gaap_CashFlowHedgingMember_019fd2c8-7159-7c96-8501-3fff13dbbefb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_019fd2c8-7224-76c1-9fa5-7d70179b9343" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019fd2c8-7224-723f-86f3-a0ad546b6829" xlink:to="loc_us-gaap_DerivativeNotionalAmount_019fd2c8-7224-76c1-9fa5-7d70179b9343" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssets_019fd2c8-7224-78bc-b271-aec865d894a7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019fd2c8-7224-723f-86f3-a0ad546b6829" xlink:to="loc_us-gaap_DerivativeAssets_019fd2c8-7224-78bc-b271-aec865d894a7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilities_019fd2c8-7224-7664-a006-d5f5fc6c1234" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019fd2c8-7224-723f-86f3-a0ad546b6829" xlink:to="loc_us-gaap_DerivativeLiabilities_019fd2c8-7224-7664-a006-d5f5fc6c1234" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/DERIVATIVESScheduleofDerivativesDesignatedasCashFlowHedgesAndDerivativeHedgesDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#DERIVATIVESScheduleofDerivativesDesignatedasCashFlowHedgesAndDerivativeHedgesDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/DERIVATIVESScheduleofDerivativesDesignatedasCashFlowHedgesAndDerivativeHedgesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_019fd2c8-7224-73c0-8b50-7ecd2ce1bf45" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_019fd2c8-7224-7848-8d37-16410495e741" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_019fd2c8-7224-73c0-8b50-7ecd2ce1bf45" xlink:to="loc_us-gaap_DerivativeTable_019fd2c8-7224-7848-8d37-16410495e741" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_019fd2c8-7224-7686-b304-b4eb1c91b771" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_019fd2c8-7224-7848-8d37-16410495e741" xlink:to="loc_us-gaap_HedgingDesignationAxis_019fd2c8-7224-7686-b304-b4eb1c91b771" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019fd2c8-7224-7686-b304-b4eb1c91b771_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_019fd2c8-7224-7686-b304-b4eb1c91b771" xlink:to="loc_us-gaap_HedgingDesignationDomain_019fd2c8-7224-7686-b304-b4eb1c91b771_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019fd2c8-7224-7f1d-8646-1b335765cf63" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_019fd2c8-7224-7686-b304-b4eb1c91b771" xlink:to="loc_us-gaap_HedgingDesignationDomain_019fd2c8-7224-7f1d-8646-1b335765cf63" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_019fd2c8-7224-7549-b0c7-81fd8e208e04" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_019fd2c8-7224-7f1d-8646-1b335765cf63" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_019fd2c8-7224-7549-b0c7-81fd8e208e04" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019fd2c8-7224-73bc-8f57-85eedd038760" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_019fd2c8-7224-7848-8d37-16410495e741" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019fd2c8-7224-73bc-8f57-85eedd038760" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_019fd2c8-7224-73bc-8f57-85eedd038760_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019fd2c8-7224-73bc-8f57-85eedd038760" xlink:to="loc_us-gaap_HedgingRelationshipDomain_019fd2c8-7224-73bc-8f57-85eedd038760_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_019fd2c8-7224-70c1-bbd3-5d97889526c9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019fd2c8-7224-73bc-8f57-85eedd038760" xlink:to="loc_us-gaap_HedgingRelationshipDomain_019fd2c8-7224-70c1-bbd3-5d97889526c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgingMember_019fd2c8-7224-7f4c-a069-321dfd92e37f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashFlowHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_019fd2c8-7224-70c1-bbd3-5d97889526c9" xlink:to="loc_us-gaap_CashFlowHedgingMember_019fd2c8-7224-7f4c-a069-321dfd92e37f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_019fd2c8-7224-7140-a19b-8003c39ded72" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019fd2c8-7224-73c0-8b50-7ecd2ce1bf45" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_019fd2c8-7224-7140-a19b-8003c39ded72" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/VARIABLEINTERESTENTITIESDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#VARIABLEINTERESTENTITIESDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/VARIABLEINTERESTENTITIESDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityLineItems_019fd2c8-7224-7133-abca-46fec6e49274" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableInterestEntityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_019fd2c8-7224-7432-b164-3a9c65fa1c84" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfVariableInterestEntitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_019fd2c8-7224-7133-abca-46fec6e49274" xlink:to="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_019fd2c8-7224-7432-b164-3a9c65fa1c84" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_019fd2c8-7224-79cd-aa2e-0872fa19c51c" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_019fd2c8-7224-7432-b164-3a9c65fa1c84" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_019fd2c8-7224-79cd-aa2e-0872fa19c51c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_019fd2c8-7224-79cd-aa2e-0872fa19c51c_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_019fd2c8-7224-79cd-aa2e-0872fa19c51c" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_019fd2c8-7224-79cd-aa2e-0872fa19c51c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_019fd2c8-7224-7ab1-af9a-bb386da6c179" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_019fd2c8-7224-79cd-aa2e-0872fa19c51c" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_019fd2c8-7224-7ab1-af9a-bb386da6c179" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_SponsoredInvestmentFundsMember_019fd2c8-7224-7cf0-946f-ef2fc9a81fb1" xlink:href="glxy-20260630.xsd#glxy_SponsoredInvestmentFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_019fd2c8-7224-7ab1-af9a-bb386da6c179" xlink:to="loc_glxy_SponsoredInvestmentFundsMember_019fd2c8-7224-7cf0-946f-ef2fc9a81fb1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_OtherVariableInterestEntitiesMember_019fd2c8-7224-7a3b-a8b8-67d1424b1514" xlink:href="glxy-20260630.xsd#glxy_OtherVariableInterestEntitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_019fd2c8-7224-7ab1-af9a-bb386da6c179" xlink:to="loc_glxy_OtherVariableInterestEntitiesMember_019fd2c8-7224-7a3b-a8b8-67d1424b1514" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_019fd2c8-7224-7900-bc8d-6a7f0790a211" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_019fd2c8-7224-7432-b164-3a9c65fa1c84" xlink:to="loc_srt_ConsolidatedEntitiesAxis_019fd2c8-7224-7900-bc8d-6a7f0790a211" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_019fd2c8-7224-7900-bc8d-6a7f0790a211_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_019fd2c8-7224-7900-bc8d-6a7f0790a211" xlink:to="loc_srt_ConsolidatedEntitiesDomain_019fd2c8-7224-7900-bc8d-6a7f0790a211_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_019fd2c8-7224-711e-82ea-557b3f891341" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_019fd2c8-7224-7900-bc8d-6a7f0790a211" xlink:to="loc_srt_ConsolidatedEntitiesDomain_019fd2c8-7224-711e-82ea-557b3f891341" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember_019fd2c8-7224-735b-9391-1d22c768f7b6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_019fd2c8-7224-711e-82ea-557b3f891341" xlink:to="loc_us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember_019fd2c8-7224-735b-9391-1d22c768f7b6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_VariableInterestEntityFairValueOfInvestment_019fd2c8-7224-733e-a9da-03d4b0dba2a9" xlink:href="glxy-20260630.xsd#glxy_VariableInterestEntityFairValueOfInvestment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_019fd2c8-7224-7133-abca-46fec6e49274" xlink:to="loc_glxy_VariableInterestEntityFairValueOfInvestment_019fd2c8-7224-733e-a9da-03d4b0dba2a9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_VariableInterestEntityUnfundedCommitments_019fd2c8-7224-7317-bc41-f805fc22f253" xlink:href="glxy-20260630.xsd#glxy_VariableInterestEntityUnfundedCommitments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_019fd2c8-7224-7133-abca-46fec6e49274" xlink:to="loc_glxy_VariableInterestEntityUnfundedCommitments_019fd2c8-7224-7317-bc41-f805fc22f253" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount_019fd2c8-7224-731a-9f31-1e569490ae87" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_019fd2c8-7224-7133-abca-46fec6e49274" xlink:to="loc_us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount_019fd2c8-7224-731a-9f31-1e569490ae87" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/FAIRVALUEOPTIONScheduleofFairValueOptionDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#FAIRVALUEOPTIONScheduleofFairValueOptionDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/FAIRVALUEOPTIONScheduleofFairValueOptionDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueOptionQuantitativeDisclosuresLineItems_019fd2c8-7224-7666-8834-d673e7651511" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueOptionQuantitativeDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueOptionQuantitativeDisclosuresTable_019fd2c8-7224-7aa7-8565-6625464e50a5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueOptionQuantitativeDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueOptionQuantitativeDisclosuresLineItems_019fd2c8-7224-7666-8834-d673e7651511" xlink:to="loc_us-gaap_FairValueOptionQuantitativeDisclosuresTable_019fd2c8-7224-7aa7-8565-6625464e50a5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019fd2c8-7224-71ff-a89f-1091a82485ed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueOptionQuantitativeDisclosuresTable_019fd2c8-7224-7aa7-8565-6625464e50a5" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019fd2c8-7224-71ff-a89f-1091a82485ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019fd2c8-7224-71ff-a89f-1091a82485ed_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019fd2c8-7224-71ff-a89f-1091a82485ed" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019fd2c8-7224-71ff-a89f-1091a82485ed_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019fd2c8-7224-74b3-9335-e999e108a30a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019fd2c8-7224-71ff-a89f-1091a82485ed" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019fd2c8-7224-74b3-9335-e999e108a30a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DigitalFinancialAssetsMember_019fd2c8-7224-7d1b-9cc1-2a5ece0c40b8" xlink:href="glxy-20260630.xsd#glxy_DigitalFinancialAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019fd2c8-7224-74b3-9335-e999e108a30a" xlink:to="loc_glxy_DigitalFinancialAssetsMember_019fd2c8-7224-7d1b-9cc1-2a5ece0c40b8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsMember_019fd2c8-7224-7cab-93fd-469e005f3b4e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019fd2c8-7224-74b3-9335-e999e108a30a" xlink:to="loc_us-gaap_InvestmentsMember_019fd2c8-7224-7cab-93fd-469e005f3b4e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_FairValueOptionAmountElected_019fd2c8-7224-7f19-830a-67b97d43968c" xlink:href="glxy-20260630.xsd#glxy_FairValueOptionAmountElected"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueOptionQuantitativeDisclosuresLineItems_019fd2c8-7224-7666-8834-d673e7651511" xlink:to="loc_glxy_FairValueOptionAmountElected_019fd2c8-7224-7f19-830a-67b97d43968c" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/FAIRVALUEOPTIONNarrativeDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#FAIRVALUEOPTIONNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/FAIRVALUEOPTIONNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueOptionQuantitativeDisclosuresLineItems_019fd2c8-7224-7fb3-8277-b6a2d89cab8b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueOptionQuantitativeDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueOptionQuantitativeDisclosuresTable_019fd2c8-7224-73fa-8237-5912f7e0f923" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueOptionQuantitativeDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueOptionQuantitativeDisclosuresLineItems_019fd2c8-7224-7fb3-8277-b6a2d89cab8b" xlink:to="loc_us-gaap_FairValueOptionQuantitativeDisclosuresTable_019fd2c8-7224-73fa-8237-5912f7e0f923" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019fd2c8-7224-7111-a83f-7b56994f9889" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueOptionQuantitativeDisclosuresTable_019fd2c8-7224-73fa-8237-5912f7e0f923" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019fd2c8-7224-7111-a83f-7b56994f9889" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019fd2c8-7224-7111-a83f-7b56994f9889_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019fd2c8-7224-7111-a83f-7b56994f9889" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019fd2c8-7224-7111-a83f-7b56994f9889_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019fd2c8-7224-700b-b000-88958c1f0017" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019fd2c8-7224-7111-a83f-7b56994f9889" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019fd2c8-7224-700b-b000-88958c1f0017" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DigitalAssetsMember_019fd2c8-7224-7465-966c-9345352ee5ca" xlink:href="glxy-20260630.xsd#glxy_DigitalAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019fd2c8-7224-700b-b000-88958c1f0017" xlink:to="loc_glxy_DigitalAssetsMember_019fd2c8-7224-7465-966c-9345352ee5ca" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnInvestments_019fd2c8-7224-73ab-a017-1b3b3707a3ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueOptionQuantitativeDisclosuresLineItems_019fd2c8-7224-7fb3-8277-b6a2d89cab8b" xlink:to="loc_us-gaap_GainLossOnInvestments_019fd2c8-7224-73ab-a017-1b3b3707a3ca" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/FAIRVALUEMEASUREMENTSScheduleofRecurringBasisatFairValueDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#FAIRVALUEMEASUREMENTSScheduleofRecurringBasisatFairValueDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/FAIRVALUEMEASUREMENTSScheduleofRecurringBasisatFairValueDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-7308-943d-dbd8902c9fd7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019fd2c8-7225-7ebf-8e8d-3638bcb85ba9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-7308-943d-dbd8902c9fd7" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019fd2c8-7225-7ebf-8e8d-3638bcb85ba9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7225-7576-be2a-58df1bcde713" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByAssetClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019fd2c8-7225-7ebf-8e8d-3638bcb85ba9" xlink:to="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7225-7576-be2a-58df1bcde713" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-7576-be2a-58df1bcde713_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7225-7576-be2a-58df1bcde713" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-7576-be2a-58df1bcde713_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-790e-b202-f4528e274882" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7225-7576-be2a-58df1bcde713" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-790e-b202-f4528e274882" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DigitalFinancialAssetsMember_019fd2c8-7225-7747-9fa1-5e35c9f73d4c" xlink:href="glxy-20260630.xsd#glxy_DigitalFinancialAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-790e-b202-f4528e274882" xlink:to="loc_glxy_DigitalFinancialAssetsMember_019fd2c8-7225-7747-9fa1-5e35c9f73d4c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DigitalIntangibleAssetsAtFairValueMember_019fd2c8-7225-7cbd-a508-b959b45f067f" xlink:href="glxy-20260630.xsd#glxy_DigitalIntangibleAssetsAtFairValueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-790e-b202-f4528e274882" xlink:to="loc_glxy_DigitalIntangibleAssetsAtFairValueMember_019fd2c8-7225-7cbd-a508-b959b45f067f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DigitalAssetsLoanReceivableNetOfAllowanceFinancialAssetsMember_019fd2c8-7225-7b4f-8586-6848972639bb" xlink:href="glxy-20260630.xsd#glxy_DigitalAssetsLoanReceivableNetOfAllowanceFinancialAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-790e-b202-f4528e274882" xlink:to="loc_glxy_DigitalAssetsLoanReceivableNetOfAllowanceFinancialAssetsMember_019fd2c8-7225-7b4f-8586-6848972639bb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DigitalAssetsReceivableMember_019fd2c8-7225-7fe1-90e5-9bc4f62b15f1" xlink:href="glxy-20260630.xsd#glxy_DigitalAssetsReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-790e-b202-f4528e274882" xlink:to="loc_glxy_DigitalAssetsReceivableMember_019fd2c8-7225-7fe1-90e5-9bc4f62b15f1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DerivativeAssetsMember_019fd2c8-7225-792c-8cc8-ed359844c54a" xlink:href="glxy-20260630.xsd#glxy_DerivativeAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-790e-b202-f4528e274882" xlink:to="loc_glxy_DerivativeAssetsMember_019fd2c8-7225-792c-8cc8-ed359844c54a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_EmbeddedDerivativeCollateralPayableDigitalAssetsMember_019fd2c8-7225-7ad2-bd9c-bc516a8772a4" xlink:href="glxy-20260630.xsd#glxy_EmbeddedDerivativeCollateralPayableDigitalAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-790e-b202-f4528e274882" xlink:to="loc_glxy_EmbeddedDerivativeCollateralPayableDigitalAssetsMember_019fd2c8-7225-7ad2-bd9c-bc516a8772a4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_EmbeddedDerivativeDigitalAssetsBorrowedMember_019fd2c8-7225-7aa2-8bd6-e4a1485f26dc" xlink:href="glxy-20260630.xsd#glxy_EmbeddedDerivativeDigitalAssetsBorrowedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-790e-b202-f4528e274882" xlink:to="loc_glxy_EmbeddedDerivativeDigitalAssetsBorrowedMember_019fd2c8-7225-7aa2-8bd6-e4a1485f26dc" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_EmbeddedDerivativeFinancialInstrumentsPayableToCustomerMember_019fd2c8-7225-7d5f-9052-56d59d4e1381" xlink:href="glxy-20260630.xsd#glxy_EmbeddedDerivativeFinancialInstrumentsPayableToCustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-790e-b202-f4528e274882" xlink:to="loc_glxy_EmbeddedDerivativeFinancialInstrumentsPayableToCustomerMember_019fd2c8-7225-7d5f-9052-56d59d4e1381" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsMember_019fd2c8-7225-7ea0-9d21-af3c6bff92b6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-790e-b202-f4528e274882" xlink:to="loc_us-gaap_InvestmentsMember_019fd2c8-7225-7ea0-9d21-af3c6bff92b6" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByLiabilityClassAxis_019fd2c8-7225-7f96-b5c9-cd51aac2b102" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByLiabilityClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019fd2c8-7225-7ebf-8e8d-3638bcb85ba9" xlink:to="loc_us-gaap_FairValueByLiabilityClassAxis_019fd2c8-7225-7f96-b5c9-cd51aac2b102" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_019fd2c8-7225-7f96-b5c9-cd51aac2b102_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_019fd2c8-7225-7f96-b5c9-cd51aac2b102" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_019fd2c8-7225-7f96-b5c9-cd51aac2b102_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_019fd2c8-7225-7486-be0f-89d67b9b7c3e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_019fd2c8-7225-7f96-b5c9-cd51aac2b102" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_019fd2c8-7225-7486-be0f-89d67b9b7c3e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_InvestmentsSoldShortMember_019fd2c8-7225-7916-bc2f-ffb7d4cf512f" xlink:href="glxy-20260630.xsd#glxy_InvestmentsSoldShortMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_019fd2c8-7225-7486-be0f-89d67b9b7c3e" xlink:to="loc_glxy_InvestmentsSoldShortMember_019fd2c8-7225-7916-bc2f-ffb7d4cf512f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DerivativeLiabilitiesMember_019fd2c8-7225-71f5-9f3c-6c2ad7b05849" xlink:href="glxy-20260630.xsd#glxy_DerivativeLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_019fd2c8-7225-7486-be0f-89d67b9b7c3e" xlink:to="loc_glxy_DerivativeLiabilitiesMember_019fd2c8-7225-71f5-9f3c-6c2ad7b05849" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_EmbeddedDerivativeDigitalAssetsBorrowedMember_019fd2c8-7225-71d9-a3ce-39685f04bf3a" xlink:href="glxy-20260630.xsd#glxy_EmbeddedDerivativeDigitalAssetsBorrowedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_019fd2c8-7225-7486-be0f-89d67b9b7c3e" xlink:to="loc_glxy_EmbeddedDerivativeDigitalAssetsBorrowedMember_019fd2c8-7225-71d9-a3ce-39685f04bf3a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_EmbeddedDerivativeCollateralPayableDigitalAssetsMember_019fd2c8-7225-7e2c-8756-8348ed695ce6" xlink:href="glxy-20260630.xsd#glxy_EmbeddedDerivativeCollateralPayableDigitalAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_019fd2c8-7225-7486-be0f-89d67b9b7c3e" xlink:to="loc_glxy_EmbeddedDerivativeCollateralPayableDigitalAssetsMember_019fd2c8-7225-7e2c-8756-8348ed695ce6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019fd2c8-7225-7057-9785-46f7b0a3bdf3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019fd2c8-7225-7ebf-8e8d-3638bcb85ba9" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019fd2c8-7225-7057-9785-46f7b0a3bdf3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-7057-9785-46f7b0a3bdf3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019fd2c8-7225-7057-9785-46f7b0a3bdf3" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-7057-9785-46f7b0a3bdf3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-7362-a6e2-5c1730bdc305" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019fd2c8-7225-7057-9785-46f7b0a3bdf3" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-7362-a6e2-5c1730bdc305" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_019fd2c8-7225-71ec-97a9-b101d94a4b9e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-7362-a6e2-5c1730bdc305" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_019fd2c8-7225-71ec-97a9-b101d94a4b9e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_019fd2c8-7225-7fa2-9d83-b8b12b3fa7aa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-7362-a6e2-5c1730bdc305" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_019fd2c8-7225-7fa2-9d83-b8b12b3fa7aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_019fd2c8-7225-7a58-a595-89e0c906255b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-7362-a6e2-5c1730bdc305" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_019fd2c8-7225-7a58-a595-89e0c906255b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_019fd2c8-7225-7cfa-a786-6f0001a7fd37" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-7308-943d-dbd8902c9fd7" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_019fd2c8-7225-7cfa-a786-6f0001a7fd37" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure_019fd2c8-7225-75e9-ab62-f88a17cb232b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-7308-943d-dbd8902c9fd7" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosure_019fd2c8-7225-75e9-ab62-f88a17cb232b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetAssetLiability_019fd2c8-7225-776f-9f1e-e6de6ea8671a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueNetAssetLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-7308-943d-dbd8902c9fd7" xlink:to="loc_us-gaap_FairValueNetAssetLiability_019fd2c8-7225-776f-9f1e-e6de6ea8671a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueAmount_019fd2c8-7225-7c39-8f57-6732b455fe65" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-7308-943d-dbd8902c9fd7" xlink:to="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueAmount_019fd2c8-7225-7c39-8f57-6732b455fe65" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/FAIRVALUEMEASUREMENTSNarrativeDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#FAIRVALUEMEASUREMENTSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/FAIRVALUEMEASUREMENTSNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-721e-a80d-161103e77da9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019fd2c8-7225-7bec-8ff5-7154e311f8df" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-721e-a80d-161103e77da9" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019fd2c8-7225-7bec-8ff5-7154e311f8df" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7225-7120-b39f-887a0a4985b4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByAssetClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019fd2c8-7225-7bec-8ff5-7154e311f8df" xlink:to="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7225-7120-b39f-887a0a4985b4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-7120-b39f-887a0a4985b4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7225-7120-b39f-887a0a4985b4" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-7120-b39f-887a0a4985b4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-7083-a3e4-692d58b4de5f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7225-7120-b39f-887a0a4985b4" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-7083-a3e4-692d58b4de5f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DigitalIntangibleAssetsMember_019fd2c8-7225-7227-8779-15f2a5be76b5" xlink:href="glxy-20260630.xsd#glxy_DigitalIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-7083-a3e4-692d58b4de5f" xlink:to="loc_glxy_DigitalIntangibleAssetsMember_019fd2c8-7225-7227-8779-15f2a5be76b5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CryptoAssetFairValue_019fd2c8-7225-74ee-aa19-0e9bb4250cee" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CryptoAssetFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-721e-a80d-161103e77da9" xlink:to="loc_us-gaap_CryptoAssetFairValue_019fd2c8-7225-74ee-aa19-0e9bb4250cee" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3_019fd2c8-7225-7e5e-9cf5-c20cffd2bbf3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-721e-a80d-161103e77da9" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3_019fd2c8-7225-7e5e-9cf5-c20cffd2bbf3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3_019fd2c8-7225-70a2-be5a-ed15e504de9c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-721e-a80d-161103e77da9" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3_019fd2c8-7225-70a2-be5a-ed15e504de9c" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/FAIRVALUEMEASUREMENTSScheduleofChangesinAssetsandLiabilitiesMeasuredandReportedatFairValueUsingLevel3InputsDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#FAIRVALUEMEASUREMENTSScheduleofChangesinAssetsandLiabilitiesMeasuredandReportedatFairValueUsingLevel3InputsDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/FAIRVALUEMEASUREMENTSScheduleofChangesinAssetsandLiabilitiesMeasuredandReportedatFairValueUsingLevel3InputsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_019fd2c8-7225-718c-8750-9c9b9ed003da" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_019fd2c8-7225-79d6-854a-160bafbea0d0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_019fd2c8-7225-718c-8750-9c9b9ed003da" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_019fd2c8-7225-79d6-854a-160bafbea0d0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7225-7c02-9d0e-efc3fab477a1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByAssetClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_019fd2c8-7225-79d6-854a-160bafbea0d0" xlink:to="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7225-7c02-9d0e-efc3fab477a1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-7c02-9d0e-efc3fab477a1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7225-7c02-9d0e-efc3fab477a1" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-7c02-9d0e-efc3fab477a1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-7a6a-ae7c-aeba97a09866" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7225-7c02-9d0e-efc3fab477a1" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-7a6a-ae7c-aeba97a09866" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DigitalIntangibleAssetsMember_019fd2c8-7225-78ec-8564-14455c340a89" xlink:href="glxy-20260630.xsd#glxy_DigitalIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-7a6a-ae7c-aeba97a09866" xlink:to="loc_glxy_DigitalIntangibleAssetsMember_019fd2c8-7225-78ec-8564-14455c340a89" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DigitalAssetsReceivableMember_019fd2c8-7225-75fa-9a8c-a421b3ce6d54" xlink:href="glxy-20260630.xsd#glxy_DigitalAssetsReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-7a6a-ae7c-aeba97a09866" xlink:to="loc_glxy_DigitalAssetsReceivableMember_019fd2c8-7225-75fa-9a8c-a421b3ce6d54" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsMember_019fd2c8-7225-778f-b2bd-fca58c685d07" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-7a6a-ae7c-aeba97a09866" xlink:to="loc_us-gaap_InvestmentsMember_019fd2c8-7225-778f-b2bd-fca58c685d07" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019fd2c8-7225-7a2c-ba99-962b803a10ee" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_019fd2c8-7225-79d6-854a-160bafbea0d0" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019fd2c8-7225-7a2c-ba99-962b803a10ee" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-7a2c-ba99-962b803a10ee_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019fd2c8-7225-7a2c-ba99-962b803a10ee" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-7a2c-ba99-962b803a10ee_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-72f2-9b2a-1bb2a60cbb08" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019fd2c8-7225-7a2c-ba99-962b803a10ee" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-72f2-9b2a-1bb2a60cbb08" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_019fd2c8-7225-7191-ab59-239a05c54d7f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-72f2-9b2a-1bb2a60cbb08" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_019fd2c8-7225-7191-ab59-239a05c54d7f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByLiabilityClassAxis_019fd2c8-7225-72e5-86eb-7eeac86c90dc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByLiabilityClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_019fd2c8-7225-79d6-854a-160bafbea0d0" xlink:to="loc_us-gaap_FairValueByLiabilityClassAxis_019fd2c8-7225-72e5-86eb-7eeac86c90dc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_019fd2c8-7225-72e5-86eb-7eeac86c90dc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_019fd2c8-7225-72e5-86eb-7eeac86c90dc" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_019fd2c8-7225-72e5-86eb-7eeac86c90dc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_019fd2c8-7225-7b57-bc46-3c278cd6a530" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_019fd2c8-7225-72e5-86eb-7eeac86c90dc" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_019fd2c8-7225-7b57-bc46-3c278cd6a530" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_EmbeddedDerivativeNotesPayableMember_019fd2c8-7225-707a-a58c-7e08068372d6" xlink:href="glxy-20260630.xsd#glxy_EmbeddedDerivativeNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_019fd2c8-7225-7b57-bc46-3c278cd6a530" xlink:to="loc_glxy_EmbeddedDerivativeNotesPayableMember_019fd2c8-7225-707a-a58c-7e08068372d6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_019fd2c8-7225-7c54-9681-d89851b0529c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_019fd2c8-7225-718c-8750-9c9b9ed003da" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_019fd2c8-7225-7c54-9681-d89851b0529c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_019fd2c8-7225-7779-adb8-7729011ba8e2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_019fd2c8-7225-7c54-9681-d89851b0529c" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_019fd2c8-7225-7779-adb8-7729011ba8e2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases_019fd2c8-7225-7830-93a4-c1d403b7bf79" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_019fd2c8-7225-7c54-9681-d89851b0529c" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases_019fd2c8-7225-7830-93a4-c1d403b7bf79" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales_019fd2c8-7225-797a-aeea-702378340182" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_019fd2c8-7225-7c54-9681-d89851b0529c" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales_019fd2c8-7225-797a-aeea-702378340182" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1_019fd2c8-7225-755c-8e25-adbe149f90d2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_019fd2c8-7225-7c54-9681-d89851b0529c" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1_019fd2c8-7225-755c-8e25-adbe149f90d2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss_019fd2c8-7225-7eba-98f0-b2b9d93bd831" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_019fd2c8-7225-7c54-9681-d89851b0529c" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss_019fd2c8-7225-7eba-98f0-b2b9d93bd831" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3_019fd2c8-7225-7d32-b04e-b2d07deacfc0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_019fd2c8-7225-7c54-9681-d89851b0529c" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3_019fd2c8-7225-7d32-b04e-b2d07deacfc0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_019fd2c8-7225-7236-b062-150a14caf4e2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_019fd2c8-7225-7978-a64c-5bd1917a5fcb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_019fd2c8-7225-718c-8750-9c9b9ed003da" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_019fd2c8-7225-7978-a64c-5bd1917a5fcb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_019fd2c8-7225-74a6-8730-057c76f4105e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_019fd2c8-7225-7978-a64c-5bd1917a5fcb" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_019fd2c8-7225-74a6-8730-057c76f4105e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityPurchases_019fd2c8-7225-7c91-8f2f-82d02a743b12" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityPurchases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_019fd2c8-7225-7978-a64c-5bd1917a5fcb" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityPurchases_019fd2c8-7225-7c91-8f2f-82d02a743b12" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySales_019fd2c8-7225-715f-b9ed-a1d44f44125a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySales"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_019fd2c8-7225-7978-a64c-5bd1917a5fcb" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySales_019fd2c8-7225-715f-b9ed-a1d44f44125a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings_019fd2c8-7225-71a7-b025-6071a0204c75" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_019fd2c8-7225-7978-a64c-5bd1917a5fcb" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings_019fd2c8-7225-71a7-b025-6071a0204c75" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisChangeInUnrealizedGainLoss_019fd2c8-7225-71a0-9b0f-6f43ee4b588f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisChangeInUnrealizedGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_019fd2c8-7225-7978-a64c-5bd1917a5fcb" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisChangeInUnrealizedGainLoss_019fd2c8-7225-71a0-9b0f-6f43ee4b588f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationLiabilityTransfersOutOfLevel3_019fd2c8-7225-77d5-8d3d-5ae0de3dd4cf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationLiabilityTransfersOutOfLevel3"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_019fd2c8-7225-7978-a64c-5bd1917a5fcb" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationLiabilityTransfersOutOfLevel3_019fd2c8-7225-77d5-8d3d-5ae0de3dd4cf" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_019fd2c8-7225-7605-89ab-3a11aa5208f6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/FAIRVALUEMEASUREMENTSScheduleofSignificantUnobservableInputsUsedforAssetsandLiabilitiesDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#FAIRVALUEMEASUREMENTSScheduleofSignificantUnobservableInputsUsedforAssetsandLiabilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/FAIRVALUEMEASUREMENTSScheduleofSignificantUnobservableInputsUsedforAssetsandLiabilitiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_019fd2c8-7225-7212-85c2-6236ad73b006" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_019fd2c8-7225-7243-a43e-8ee1714cc92c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_019fd2c8-7225-7212-85c2-6236ad73b006" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_019fd2c8-7225-7243-a43e-8ee1714cc92c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019fd2c8-7225-7983-a3e0-9a7d18847030" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_019fd2c8-7225-7243-a43e-8ee1714cc92c" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019fd2c8-7225-7983-a3e0-9a7d18847030" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-7983-a3e0-9a7d18847030_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019fd2c8-7225-7983-a3e0-9a7d18847030" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-7983-a3e0-9a7d18847030_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-718b-9dff-f6ef00e3bd8c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019fd2c8-7225-7983-a3e0-9a7d18847030" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-718b-9dff-f6ef00e3bd8c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_019fd2c8-7225-72e5-81eb-70c97d0c36f0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-718b-9dff-f6ef00e3bd8c" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_019fd2c8-7225-72e5-81eb-70c97d0c36f0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019fd2c8-7225-7bd7-8d3f-f098f5f1f149" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_019fd2c8-7225-7243-a43e-8ee1714cc92c" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019fd2c8-7225-7bd7-8d3f-f098f5f1f149" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019fd2c8-7225-7bd7-8d3f-f098f5f1f149_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019fd2c8-7225-7bd7-8d3f-f098f5f1f149" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019fd2c8-7225-7bd7-8d3f-f098f5f1f149_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019fd2c8-7225-7ed2-a245-f6ab6d649033" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019fd2c8-7225-7bd7-8d3f-f098f5f1f149" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019fd2c8-7225-7ed2-a245-f6ab6d649033" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DigitalAssetsReceivableMember_019fd2c8-7225-7c1b-bfc1-15fd5bf22109" xlink:href="glxy-20260630.xsd#glxy_DigitalAssetsReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019fd2c8-7225-7ed2-a245-f6ab6d649033" xlink:to="loc_glxy_DigitalAssetsReceivableMember_019fd2c8-7225-7c1b-bfc1-15fd5bf22109" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsMember_019fd2c8-7225-7f40-9347-fc86d1b02454" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019fd2c8-7225-7ed2-a245-f6ab6d649033" xlink:to="loc_us-gaap_InvestmentsMember_019fd2c8-7225-7f40-9347-fc86d1b02454" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_019fd2c8-7225-756a-a12e-9d1f42e0031c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_019fd2c8-7225-7243-a43e-8ee1714cc92c" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_019fd2c8-7225-756a-a12e-9d1f42e0031c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_019fd2c8-7225-756a-a12e-9d1f42e0031c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_019fd2c8-7225-756a-a12e-9d1f42e0031c" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_019fd2c8-7225-756a-a12e-9d1f42e0031c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_019fd2c8-7225-7962-b3fa-fa1effea8083" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_019fd2c8-7225-756a-a12e-9d1f42e0031c" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_019fd2c8-7225-7962-b3fa-fa1effea8083" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_MarketabilityDiscountMember_019fd2c8-7225-7b8b-b566-5afaf0b4f489" xlink:href="glxy-20260630.xsd#glxy_MarketabilityDiscountMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_019fd2c8-7225-7962-b3fa-fa1effea8083" xlink:to="loc_glxy_MarketabilityDiscountMember_019fd2c8-7225-7b8b-b566-5afaf0b4f489" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_TimeToLiquidityEventYearsMember_019fd2c8-7225-7651-8046-231051916356" xlink:href="glxy-20260630.xsd#glxy_TimeToLiquidityEventYearsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_019fd2c8-7225-7962-b3fa-fa1effea8083" xlink:to="loc_glxy_TimeToLiquidityEventYearsMember_019fd2c8-7225-7651-8046-231051916356" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_AnnualizedEquityVolatilityMember_019fd2c8-7225-794b-9c89-0f5b3f082262" xlink:href="glxy-20260630.xsd#glxy_AnnualizedEquityVolatilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_019fd2c8-7225-7962-b3fa-fa1effea8083" xlink:to="loc_glxy_AnnualizedEquityVolatilityMember_019fd2c8-7225-794b-9c89-0f5b3f082262" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputRiskFreeInterestRateMember_019fd2c8-7225-7ddc-add7-eb357e800bf3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputRiskFreeInterestRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_019fd2c8-7225-7962-b3fa-fa1effea8083" xlink:to="loc_us-gaap_MeasurementInputRiskFreeInterestRateMember_019fd2c8-7225-7ddc-add7-eb357e800bf3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_MarketAdjustmentDiscountMember_019fd2c8-7225-762b-841a-9c447dea0b66" xlink:href="glxy-20260630.xsd#glxy_MarketAdjustmentDiscountMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_019fd2c8-7225-7962-b3fa-fa1effea8083" xlink:to="loc_glxy_MarketAdjustmentDiscountMember_019fd2c8-7225-762b-841a-9c447dea0b66" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_MarketAdjustmentPremiumMember_019fd2c8-7225-74d4-a136-a9f5dd08859d" xlink:href="glxy-20260630.xsd#glxy_MarketAdjustmentPremiumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_019fd2c8-7225-7962-b3fa-fa1effea8083" xlink:to="loc_glxy_MarketAdjustmentPremiumMember_019fd2c8-7225-74d4-a136-a9f5dd08859d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_ExpectedDividendPayoutRatioMember_019fd2c8-7225-7398-9699-d9910cc2c8c7" xlink:href="glxy-20260630.xsd#glxy_ExpectedDividendPayoutRatioMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_019fd2c8-7225-7962-b3fa-fa1effea8083" xlink:to="loc_glxy_ExpectedDividendPayoutRatioMember_019fd2c8-7225-7398-9699-d9910cc2c8c7" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_EnterpriseValueToLTMRevenueMultipleMember_019fd2c8-7225-7938-8b41-0d0b26606a3e" xlink:href="glxy-20260630.xsd#glxy_EnterpriseValueToLTMRevenueMultipleMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_019fd2c8-7225-7962-b3fa-fa1effea8083" xlink:to="loc_glxy_EnterpriseValueToLTMRevenueMultipleMember_019fd2c8-7225-7938-8b41-0d0b26606a3e" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_EnterpriseValueToProjectedRevenueMultipleMember_019fd2c8-7225-78a9-ac71-03006f544398" xlink:href="glxy-20260630.xsd#glxy_EnterpriseValueToProjectedRevenueMultipleMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_019fd2c8-7225-7962-b3fa-fa1effea8083" xlink:to="loc_glxy_EnterpriseValueToProjectedRevenueMultipleMember_019fd2c8-7225-78a9-ac71-03006f544398" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_EnterpriseValueToAnnualizedRevenueMember_019fd2c8-7225-7369-bd03-fabe983cb0b0" xlink:href="glxy-20260630.xsd#glxy_EnterpriseValueToAnnualizedRevenueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_019fd2c8-7225-7962-b3fa-fa1effea8083" xlink:to="loc_glxy_EnterpriseValueToAnnualizedRevenueMember_019fd2c8-7225-7369-bd03-fabe983cb0b0" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_EnterpriseValueToARRMember_019fd2c8-7225-770c-9929-826720920d8a" xlink:href="glxy-20260630.xsd#glxy_EnterpriseValueToARRMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_019fd2c8-7225-7962-b3fa-fa1effea8083" xlink:to="loc_glxy_EnterpriseValueToARRMember_019fd2c8-7225-770c-9929-826720920d8a" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_EnterpriseValueToGrossProfitMember_019fd2c8-7225-750c-9080-ae39b2e4e899" xlink:href="glxy-20260630.xsd#glxy_EnterpriseValueToGrossProfitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_019fd2c8-7225-7962-b3fa-fa1effea8083" xlink:to="loc_glxy_EnterpriseValueToGrossProfitMember_019fd2c8-7225-750c-9080-ae39b2e4e899" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_RecoveryPercentageMember_019fd2c8-7225-7dc2-b197-ab625d9e1e08" xlink:href="glxy-20260630.xsd#glxy_RecoveryPercentageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_019fd2c8-7225-7962-b3fa-fa1effea8083" xlink:to="loc_glxy_RecoveryPercentageMember_019fd2c8-7225-7dc2-b197-ab625d9e1e08" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019fd2c8-7225-779c-8397-87b5bdcb4b47" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_019fd2c8-7225-7243-a43e-8ee1714cc92c" xlink:to="loc_srt_RangeAxis_019fd2c8-7225-779c-8397-87b5bdcb4b47" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fd2c8-7225-779c-8397-87b5bdcb4b47_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019fd2c8-7225-779c-8397-87b5bdcb4b47" xlink:to="loc_srt_RangeMember_019fd2c8-7225-779c-8397-87b5bdcb4b47_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fd2c8-7225-7c0f-b790-aeff68aa5dcc" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019fd2c8-7225-779c-8397-87b5bdcb4b47" xlink:to="loc_srt_RangeMember_019fd2c8-7225-7c0f-b790-aeff68aa5dcc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019fd2c8-7225-7da7-b875-25d1d5e1e8f0" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019fd2c8-7225-7c0f-b790-aeff68aa5dcc" xlink:to="loc_srt_MinimumMember_019fd2c8-7225-7da7-b875-25d1d5e1e8f0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019fd2c8-7225-7da0-9f48-062085089976" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019fd2c8-7225-7c0f-b790-aeff68aa5dcc" xlink:to="loc_srt_MaximumMember_019fd2c8-7225-7da0-9f48-062085089976" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_WeightedAverageMember_019fd2c8-7225-7854-8ffd-257340578cc5" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_WeightedAverageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019fd2c8-7225-7c0f-b790-aeff68aa5dcc" xlink:to="loc_srt_WeightedAverageMember_019fd2c8-7225-7854-8ffd-257340578cc5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7225-73f2-8a3b-1e41eb117196" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByAssetClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_019fd2c8-7225-7243-a43e-8ee1714cc92c" xlink:to="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7225-73f2-8a3b-1e41eb117196" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-73f2-8a3b-1e41eb117196_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7225-73f2-8a3b-1e41eb117196" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-73f2-8a3b-1e41eb117196_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-7d76-97ee-aa900389ac26" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_019fd2c8-7225-73f2-8a3b-1e41eb117196" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-7d76-97ee-aa900389ac26" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsMember_019fd2c8-7225-7761-a707-61fe4b789528" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019fd2c8-7225-7d76-97ee-aa900389ac26" xlink:to="loc_us-gaap_InvestmentsMember_019fd2c8-7225-7761-a707-61fe4b789528" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_019fd2c8-7225-7ffe-91f6-1aa9f7a748ab" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_019fd2c8-7225-7212-85c2-6236ad73b006" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_019fd2c8-7225-7ffe-91f6-1aa9f7a748ab" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetReceivableMeasurementInput_019fd2c8-7225-7de7-9e96-261cceece951" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetReceivableMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_019fd2c8-7225-7212-85c2-6236ad73b006" xlink:to="loc_glxy_CryptoAssetReceivableMeasurementInput_019fd2c8-7225-7de7-9e96-261cceece951" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesTradingMeasurementInput_019fd2c8-7225-7ca7-85f2-c96b962c0339" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesTradingMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_019fd2c8-7225-7212-85c2-6236ad73b006" xlink:to="loc_us-gaap_DebtSecuritiesTradingMeasurementInput_019fd2c8-7225-7ca7-85f2-c96b962c0339" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/FAIRVALUEMEASUREMENTSScheduleofFinancialInstrumentsnotMeasuredatFairValueDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#FAIRVALUEMEASUREMENTSScheduleofFinancialInstrumentsnotMeasuredatFairValueDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/FAIRVALUEMEASUREMENTSScheduleofFinancialInstrumentsnotMeasuredatFairValueDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-7239-b51b-d3aa305432e9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019fd2c8-7225-7218-be4b-ce2940d84ffb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-7239-b51b-d3aa305432e9" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019fd2c8-7225-7218-be4b-ce2940d84ffb" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_019fd2c8-7225-7552-81ce-d1eb958eaedf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019fd2c8-7225-7218-be4b-ce2940d84ffb" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_019fd2c8-7225-7552-81ce-d1eb958eaedf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019fd2c8-7225-7552-81ce-d1eb958eaedf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_019fd2c8-7225-7552-81ce-d1eb958eaedf" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019fd2c8-7225-7552-81ce-d1eb958eaedf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019fd2c8-7225-7139-890e-7b0f795ba658" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_019fd2c8-7225-7552-81ce-d1eb958eaedf" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019fd2c8-7225-7139-890e-7b0f795ba658" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019fd2c8-7225-7fec-bc9d-b28bd2444de2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019fd2c8-7225-7139-890e-7b0f795ba658" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019fd2c8-7225-7fec-bc9d-b28bd2444de2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_019fd2c8-7225-79c8-93df-adae404d79db" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019fd2c8-7225-7fec-bc9d-b28bd2444de2" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_019fd2c8-7225-79c8-93df-adae404d79db" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_019fd2c8-7225-7dfd-89b1-757246311a80" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019fd2c8-7225-7fec-bc9d-b28bd2444de2" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_019fd2c8-7225-7dfd-89b1-757246311a80" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019fd2c8-7225-711b-a3b6-62a80b5488de" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019fd2c8-7225-7218-be4b-ce2940d84ffb" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019fd2c8-7225-711b-a3b6-62a80b5488de" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-711b-a3b6-62a80b5488de_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019fd2c8-7225-711b-a3b6-62a80b5488de" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-711b-a3b6-62a80b5488de_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-74ab-808d-4aed8637fab5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019fd2c8-7225-711b-a3b6-62a80b5488de" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-74ab-808d-4aed8637fab5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_019fd2c8-7225-739c-a0dd-b5526312586c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-74ab-808d-4aed8637fab5" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_019fd2c8-7225-739c-a0dd-b5526312586c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_019fd2c8-7225-756d-9acc-fee50693136b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-74ab-808d-4aed8637fab5" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_019fd2c8-7225-756d-9acc-fee50693136b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_019fd2c8-7225-73ef-9e41-74823043763c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019fd2c8-7225-74ab-808d-4aed8637fab5" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_019fd2c8-7225-73ef-9e41-74823043763c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_019fd2c8-7225-733e-9205-f127b6bf1cc8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-7239-b51b-d3aa305432e9" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_019fd2c8-7225-733e-9205-f127b6bf1cc8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_AssetsPostedAsCollateralCash_019fd2c8-7225-7491-8ad3-9f4438ab5feb" xlink:href="glxy-20260630.xsd#glxy_AssetsPostedAsCollateralCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-7239-b51b-d3aa305432e9" xlink:to="loc_glxy_AssetsPostedAsCollateralCash_019fd2c8-7225-7491-8ad3-9f4438ab5feb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableFairValueDisclosure_019fd2c8-7225-7cf2-8b8b-3c4a3dd7a180" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-7239-b51b-d3aa305432e9" xlink:to="loc_us-gaap_AccountsReceivableFairValueDisclosure_019fd2c8-7225-7cf2-8b8b-3c4a3dd7a180" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansReceivableFairValueDisclosure_019fd2c8-7225-74b2-b1ee-527043b0179e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LoansReceivableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-7239-b51b-d3aa305432e9" xlink:to="loc_us-gaap_LoansReceivableFairValueDisclosure_019fd2c8-7225-74b2-b1ee-527043b0179e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_AssetsFairValueDisclosureExcludingNonFinancialAssets_019fd2c8-7225-73b8-9694-5acfa70dc44e" xlink:href="glxy-20260630.xsd#glxy_AssetsFairValueDisclosureExcludingNonFinancialAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-7239-b51b-d3aa305432e9" xlink:to="loc_glxy_AssetsFairValueDisclosureExcludingNonFinancialAssets_019fd2c8-7225-73b8-9694-5acfa70dc44e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_019fd2c8-7225-71ab-86be-01a4e4732e5b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-7239-b51b-d3aa305432e9" xlink:to="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_019fd2c8-7225-71ab-86be-01a4e4732e5b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableFairValueDisclosure_019fd2c8-7225-7724-a176-9b93cc9d89ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesPayableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-7239-b51b-d3aa305432e9" xlink:to="loc_us-gaap_NotesPayableFairValueDisclosure_019fd2c8-7225-7724-a176-9b93cc9d89ca" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CollateralPayableCash_019fd2c8-7225-7da6-84a4-6cdd4aa84d2e" xlink:href="glxy-20260630.xsd#glxy_CollateralPayableCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-7239-b51b-d3aa305432e9" xlink:to="loc_glxy_CollateralPayableCash_019fd2c8-7225-7da6-84a4-6cdd4aa84d2e" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_PayableToCustomersCash_019fd2c8-7225-7d71-890b-a1043ae3b4ee" xlink:href="glxy-20260630.xsd#glxy_PayableToCustomersCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-7239-b51b-d3aa305432e9" xlink:to="loc_glxy_PayableToCustomersCash_019fd2c8-7225-7d71-890b-a1043ae3b4ee" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansPayableFairValueDisclosure_019fd2c8-7225-7057-abb5-9e1576b0e5c3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LoansPayableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-7239-b51b-d3aa305432e9" xlink:to="loc_us-gaap_LoansPayableFairValueDisclosure_019fd2c8-7225-7057-abb5-9e1576b0e5c3" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SettlementLiabilitiesCurrent_019fd2c8-7225-717b-86c7-18f142d62fa1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SettlementLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-7239-b51b-d3aa305432e9" xlink:to="loc_us-gaap_SettlementLiabilitiesCurrent_019fd2c8-7225-717b-86c7-18f142d62fa1" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_LiabilitiesFairValueDisclosureExcludingNonFinancialLiabilities_019fd2c8-7225-7b67-9818-10414b622545" xlink:href="glxy-20260630.xsd#glxy_LiabilitiesFairValueDisclosureExcludingNonFinancialLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019fd2c8-7225-7239-b51b-d3aa305432e9" xlink:to="loc_glxy_LiabilitiesFairValueDisclosureExcludingNonFinancialLiabilities_019fd2c8-7225-7b67-9818-10414b622545" xlink:type="arc" order="11"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/LOANSRECEIVABLEScheduleofCollateralPayableAssociatedWithLoansReceivableCurrentDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#LOANSRECEIVABLEScheduleofCollateralPayableAssociatedWithLoansReceivableCurrentDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/LOANSRECEIVABLEScheduleofCollateralPayableAssociatedWithLoansReceivableCurrentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fd2c8-7225-7a85-9906-21844ba7c4b9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fd2c8-7225-7297-9db9-d165d0eb0083" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fd2c8-7225-7a85-9906-21844ba7c4b9" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fd2c8-7225-7297-9db9-d165d0eb0083" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralAxis_019fd2c8-7225-7546-a5ed-a7dcfce9ac7a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollateralAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019fd2c8-7225-7297-9db9-d165d0eb0083" xlink:to="loc_us-gaap_CollateralAxis_019fd2c8-7225-7546-a5ed-a7dcfce9ac7a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralDomain_019fd2c8-7225-7546-a5ed-a7dcfce9ac7a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollateralDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CollateralAxis_019fd2c8-7225-7546-a5ed-a7dcfce9ac7a" xlink:to="loc_us-gaap_CollateralDomain_019fd2c8-7225-7546-a5ed-a7dcfce9ac7a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralDomain_019fd2c8-7225-7641-8ca3-9a73070d44a3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollateralDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CollateralAxis_019fd2c8-7225-7546-a5ed-a7dcfce9ac7a" xlink:to="loc_us-gaap_CollateralDomain_019fd2c8-7225-7641-8ca3-9a73070d44a3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DigitalAssetsMember_019fd2c8-7225-7326-9432-ab9bd2244e88" xlink:href="glxy-20260630.xsd#glxy_DigitalAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollateralDomain_019fd2c8-7225-7641-8ca3-9a73070d44a3" xlink:to="loc_glxy_DigitalAssetsMember_019fd2c8-7225-7326-9432-ab9bd2244e88" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CashCollateralMember_019fd2c8-7225-7ad4-a9f7-b563d5c05dcc" xlink:href="glxy-20260630.xsd#glxy_CashCollateralMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollateralDomain_019fd2c8-7225-7641-8ca3-9a73070d44a3" xlink:to="loc_glxy_CashCollateralMember_019fd2c8-7225-7ad4-a9f7-b563d5c05dcc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralizedFinancings_019fd2c8-7225-7808-82ea-ec336414b184" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollateralizedFinancings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019fd2c8-7225-7a85-9906-21844ba7c4b9" xlink:to="loc_us-gaap_CollateralizedFinancings_019fd2c8-7225-7808-82ea-ec336414b184" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/PROPERTYANDEQUIPMENTScheduleofPropertyandEquipmentDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#PROPERTYANDEQUIPMENTScheduleofPropertyandEquipmentDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/PROPERTYANDEQUIPMENTScheduleofPropertyandEquipmentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fd2c8-7225-7469-906a-1a82409ff422" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019fd2c8-7225-79da-a43f-6e0452e2f583" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fd2c8-7225-7469-906a-1a82409ff422" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019fd2c8-7225-79da-a43f-6e0452e2f583" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019fd2c8-7225-7b9f-985a-7e5769cdca85" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019fd2c8-7225-79da-a43f-6e0452e2f583" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019fd2c8-7225-7b9f-985a-7e5769cdca85" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019fd2c8-7225-7b9f-985a-7e5769cdca85_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019fd2c8-7225-7b9f-985a-7e5769cdca85" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019fd2c8-7225-7b9f-985a-7e5769cdca85_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019fd2c8-7225-789e-9079-d7673c1414fd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019fd2c8-7225-7b9f-985a-7e5769cdca85" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019fd2c8-7225-789e-9079-d7673c1414fd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CorporateAssetsMember_019fd2c8-7225-7223-a8f6-8cb866074739" xlink:href="glxy-20260630.xsd#glxy_CorporateAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019fd2c8-7225-789e-9079-d7673c1414fd" xlink:to="loc_glxy_CorporateAssetsMember_019fd2c8-7225-7223-a8f6-8cb866074739" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_MiningEquipmentMember_019fd2c8-7225-71d8-8212-bb2ee89136b6" xlink:href="glxy-20260630.xsd#glxy_MiningEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019fd2c8-7225-789e-9079-d7673c1414fd" xlink:to="loc_glxy_MiningEquipmentMember_019fd2c8-7225-71d8-8212-bb2ee89136b6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DataCenterInfrastructureMember_019fd2c8-7225-7c6f-8a7e-81b6e01035c8" xlink:href="glxy-20260630.xsd#glxy_DataCenterInfrastructureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019fd2c8-7225-789e-9079-d7673c1414fd" xlink:to="loc_glxy_DataCenterInfrastructureMember_019fd2c8-7225-7c6f-8a7e-81b6e01035c8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LandMember_019fd2c8-7225-7db8-a4a1-8beb60897bd0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LandMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019fd2c8-7225-789e-9079-d7673c1414fd" xlink:to="loc_us-gaap_LandMember_019fd2c8-7225-7db8-a4a1-8beb60897bd0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressMember_019fd2c8-7225-71b7-80e2-b9b6ff836643" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConstructionInProgressMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019fd2c8-7225-789e-9079-d7673c1414fd" xlink:to="loc_us-gaap_ConstructionInProgressMember_019fd2c8-7225-71b7-80e2-b9b6ff836643" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_019fd2c8-7225-7848-aa9c-add0d1e31b1f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fd2c8-7225-7469-906a-1a82409ff422" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_019fd2c8-7225-7848-aa9c-add0d1e31b1f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_019fd2c8-7225-77d1-8b59-578ec0b5a379" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fd2c8-7225-7469-906a-1a82409ff422" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_019fd2c8-7225-77d1-8b59-578ec0b5a379" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_ImpairedAssetsToBeDisposedOfByMethodOtherThanSaleAmountOfLoss_019fd2c8-7225-7e38-97ff-cfe0461a9917" xlink:href="glxy-20260630.xsd#glxy_ImpairedAssetsToBeDisposedOfByMethodOtherThanSaleAmountOfLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fd2c8-7225-7469-906a-1a82409ff422" xlink:to="loc_glxy_ImpairedAssetsToBeDisposedOfByMethodOtherThanSaleAmountOfLoss_019fd2c8-7225-7e38-97ff-cfe0461a9917" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_019fd2c8-7225-74ff-a812-665fe515b795" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fd2c8-7225-7469-906a-1a82409ff422" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_019fd2c8-7225-74ff-a812-665fe515b795" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/PROPERTYANDEQUIPMENTNarrativeDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#PROPERTYANDEQUIPMENTNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/PROPERTYANDEQUIPMENTNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fd2c8-7225-7c1c-9cf5-b4ae2909d9b4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019fd2c8-7225-76ce-96ed-81b8200d2276" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fd2c8-7225-7c1c-9cf5-b4ae2909d9b4" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019fd2c8-7225-76ce-96ed-81b8200d2276" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019fd2c8-7225-73f2-9cc1-ab0cdfbe57fa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019fd2c8-7225-76ce-96ed-81b8200d2276" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019fd2c8-7225-73f2-9cc1-ab0cdfbe57fa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019fd2c8-7225-73f2-9cc1-ab0cdfbe57fa_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019fd2c8-7225-73f2-9cc1-ab0cdfbe57fa" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019fd2c8-7225-73f2-9cc1-ab0cdfbe57fa_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019fd2c8-7225-7ab0-9348-50ce1cd04e99" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019fd2c8-7225-73f2-9cc1-ab0cdfbe57fa" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019fd2c8-7225-7ab0-9348-50ce1cd04e99" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_MiningEquipmentMember_019fd2c8-7225-78be-b27d-777ef34c9ebb" xlink:href="glxy-20260630.xsd#glxy_MiningEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019fd2c8-7225-7ab0-9348-50ce1cd04e99" xlink:to="loc_glxy_MiningEquipmentMember_019fd2c8-7225-78be-b27d-777ef34c9ebb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation_019fd2c8-7225-79c9-9bdf-802adc6e3857" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Depreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fd2c8-7225-7c1c-9cf5-b4ae2909d9b4" xlink:to="loc_us-gaap_Depreciation_019fd2c8-7225-79c9-9bdf-802adc6e3857" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TangibleAssetImpairmentCharges_019fd2c8-7225-70c9-bf68-f19379e8d9f3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TangibleAssetImpairmentCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019fd2c8-7225-7c1c-9cf5-b4ae2909d9b4" xlink:to="loc_us-gaap_TangibleAssetImpairmentCharges_019fd2c8-7225-70c9-bf68-f19379e8d9f3" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/GOODWILLANDOTHERINTANGIBLEASSETSScheduleofIntangibleAssetsDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#GOODWILLANDOTHERINTANGIBLEASSETSScheduleofIntangibleAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/GOODWILLANDOTHERINTANGIBLEASSETSScheduleofIntangibleAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019fd2c8-7225-7d1b-bd94-9d4eadb92f69" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019fd2c8-7225-7a73-9c73-fb9b089e93d6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019fd2c8-7225-7d1b-bd94-9d4eadb92f69" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019fd2c8-7225-7a73-9c73-fb9b089e93d6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019fd2c8-7225-75b5-902b-523037416761" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019fd2c8-7225-7a73-9c73-fb9b089e93d6" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019fd2c8-7225-75b5-902b-523037416761" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019fd2c8-7225-75b5-902b-523037416761_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019fd2c8-7225-75b5-902b-523037416761" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019fd2c8-7225-75b5-902b-523037416761_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019fd2c8-7225-74ae-af55-3964de0a63e2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019fd2c8-7225-75b5-902b-523037416761" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019fd2c8-7225-74ae-af55-3964de0a63e2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TechnologyBasedIntangibleAssetsMember_019fd2c8-7225-74c8-975c-4d3ff2f3afbd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TechnologyBasedIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019fd2c8-7225-74ae-af55-3964de0a63e2" xlink:to="loc_us-gaap_TechnologyBasedIntangibleAssetsMember_019fd2c8-7225-74c8-975c-4d3ff2f3afbd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIntangibleAssetsMember_019fd2c8-7225-7781-af2b-fe4e6954ee4a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019fd2c8-7225-74ae-af55-3964de0a63e2" xlink:to="loc_us-gaap_OtherIntangibleAssetsMember_019fd2c8-7225-7781-af2b-fe4e6954ee4a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_019fd2c8-7225-7610-9b57-a7c34f3ddbbc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019fd2c8-7225-7d1b-bd94-9d4eadb92f69" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_019fd2c8-7225-7610-9b57-a7c34f3ddbbc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_019fd2c8-7225-771e-ab71-6c6c8baaa50e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019fd2c8-7225-7d1b-bd94-9d4eadb92f69" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_019fd2c8-7225-771e-ab71-6c6c8baaa50e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsGrossExcludingGoodwill_019fd2c8-7225-7bfe-b006-46c1a3356a29" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IntangibleAssetsGrossExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019fd2c8-7225-7d1b-bd94-9d4eadb92f69" xlink:to="loc_us-gaap_IntangibleAssetsGrossExcludingGoodwill_019fd2c8-7225-7bfe-b006-46c1a3356a29" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_019fd2c8-7225-7380-8795-22da80924540" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019fd2c8-7225-7d1b-bd94-9d4eadb92f69" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_019fd2c8-7225-7380-8795-22da80924540" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_019fd2c8-7225-792d-8158-da57a11771f1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019fd2c8-7225-7d1b-bd94-9d4eadb92f69" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_019fd2c8-7225-792d-8158-da57a11771f1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount_019fd2c8-7225-7809-9eba-bbb607b3e8ed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019fd2c8-7225-7d1b-bd94-9d4eadb92f69" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount_019fd2c8-7225-7809-9eba-bbb607b3e8ed" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/COMMITMENTSANDCONTINGENCIESDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#COMMITMENTSANDCONTINGENCIESDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/COMMITMENTSANDCONTINGENCIESDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsLineItems_019fd2c8-7225-763a-b671-4eecf22ebc0c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherCommitmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsTable_019fd2c8-7225-7ea1-87b0-c9646d2c8af2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherCommitmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_019fd2c8-7225-763a-b671-4eecf22ebc0c" xlink:to="loc_us-gaap_OtherCommitmentsTable_019fd2c8-7225-7ea1-87b0-c9646d2c8af2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionTypeAxis_019fd2c8-7225-798a-8ae3-55de87a3e452" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransactionTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OtherCommitmentsTable_019fd2c8-7225-7ea1-87b0-c9646d2c8af2" xlink:to="loc_us-gaap_TransactionTypeAxis_019fd2c8-7225-798a-8ae3-55de87a3e452" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionDomain_019fd2c8-7225-798a-8ae3-55de87a3e452_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TransactionTypeAxis_019fd2c8-7225-798a-8ae3-55de87a3e452" xlink:to="loc_us-gaap_TransactionDomain_019fd2c8-7225-798a-8ae3-55de87a3e452_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionDomain_019fd2c8-7225-757b-b5b2-12f76e788119" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TransactionTypeAxis_019fd2c8-7225-798a-8ae3-55de87a3e452" xlink:to="loc_us-gaap_TransactionDomain_019fd2c8-7225-757b-b5b2-12f76e788119" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_SubleasesMember_019fd2c8-7225-76ee-8543-ad74bf2a9b10" xlink:href="glxy-20260630.xsd#glxy_SubleasesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransactionDomain_019fd2c8-7225-757b-b5b2-12f76e788119" xlink:to="loc_glxy_SubleasesMember_019fd2c8-7225-76ee-8543-ad74bf2a9b10" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsAxis_019fd2c8-7225-71a5-9f47-5d816e70f3e4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherCommitmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OtherCommitmentsTable_019fd2c8-7225-7ea1-87b0-c9646d2c8af2" xlink:to="loc_us-gaap_OtherCommitmentsAxis_019fd2c8-7225-71a5-9f47-5d816e70f3e4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsDomain_019fd2c8-7225-71a5-9f47-5d816e70f3e4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherCommitmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OtherCommitmentsAxis_019fd2c8-7225-71a5-9f47-5d816e70f3e4" xlink:to="loc_us-gaap_OtherCommitmentsDomain_019fd2c8-7225-71a5-9f47-5d816e70f3e4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsDomain_019fd2c8-7225-7033-806b-1eee8ab6677c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherCommitmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OtherCommitmentsAxis_019fd2c8-7225-71a5-9f47-5d816e70f3e4" xlink:to="loc_us-gaap_OtherCommitmentsDomain_019fd2c8-7225-7033-806b-1eee8ab6677c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CreditFacilityFundingAndDelayedTradingSettlementsMember_019fd2c8-7225-7ead-a46b-5c1d0038ba68" xlink:href="glxy-20260630.xsd#glxy_CreditFacilityFundingAndDelayedTradingSettlementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsDomain_019fd2c8-7225-7033-806b-1eee8ab6677c" xlink:to="loc_glxy_CreditFacilityFundingAndDelayedTradingSettlementsMember_019fd2c8-7225-7ead-a46b-5c1d0038ba68" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_FacilityConstructionImprovementsMember_019fd2c8-7225-7be9-a869-d00d1905e14a" xlink:href="glxy-20260630.xsd#glxy_FacilityConstructionImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsDomain_019fd2c8-7225-7033-806b-1eee8ab6677c" xlink:to="loc_glxy_FacilityConstructionImprovementsMember_019fd2c8-7225-7be9-a869-d00d1905e14a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_019fd2c8-7225-7e7d-bd3c-28c02d5b904a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OtherCommitmentsTable_019fd2c8-7225-7ea1-87b0-c9646d2c8af2" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_019fd2c8-7225-7e7d-bd3c-28c02d5b904a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019fd2c8-7225-7e7d-bd3c-28c02d5b904a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019fd2c8-7225-7e7d-bd3c-28c02d5b904a" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019fd2c8-7225-7e7d-bd3c-28c02d5b904a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019fd2c8-7225-7926-8872-5b43193bcc30" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019fd2c8-7225-7e7d-bd3c-28c02d5b904a" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019fd2c8-7225-7926-8872-5b43193bcc30" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_019fd2c8-7225-7161-935c-8a284feb6016" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_019fd2c8-7225-7926-8872-5b43193bcc30" xlink:to="loc_us-gaap_SubsequentEventMember_019fd2c8-7225-7161-935c-8a284feb6016" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_019fd2c8-7225-73ce-99d7-a4e73f9bcb0d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingenciesByNatureOfContingencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OtherCommitmentsTable_019fd2c8-7225-7ea1-87b0-c9646d2c8af2" xlink:to="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_019fd2c8-7225-73ce-99d7-a4e73f9bcb0d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_019fd2c8-7225-73ce-99d7-a4e73f9bcb0d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingencyNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_019fd2c8-7225-73ce-99d7-a4e73f9bcb0d" xlink:to="loc_us-gaap_LossContingencyNatureDomain_019fd2c8-7225-73ce-99d7-a4e73f9bcb0d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_019fd2c8-7225-78f2-8ae0-7f23d2cd4ee2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingencyNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_019fd2c8-7225-73ce-99d7-a4e73f9bcb0d" xlink:to="loc_us-gaap_LossContingencyNatureDomain_019fd2c8-7225-78f2-8ae0-7f23d2cd4ee2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndemnificationGuaranteeMember_019fd2c8-7225-774e-b2b4-268a2d515651" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IndemnificationGuaranteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingencyNatureDomain_019fd2c8-7225-78f2-8ae0-7f23d2cd4ee2" xlink:to="loc_us-gaap_IndemnificationGuaranteeMember_019fd2c8-7225-774e-b2b4-268a2d515651" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementScenarioAxis_019fd2c8-7225-7fad-80a4-0a0a3ac5bc84" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementScenarioAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OtherCommitmentsTable_019fd2c8-7225-7ea1-87b0-c9646d2c8af2" xlink:to="loc_srt_StatementScenarioAxis_019fd2c8-7225-7fad-80a4-0a0a3ac5bc84" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_019fd2c8-7225-7fad-80a4-0a0a3ac5bc84_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementScenarioAxis_019fd2c8-7225-7fad-80a4-0a0a3ac5bc84" xlink:to="loc_srt_ScenarioUnspecifiedDomain_019fd2c8-7225-7fad-80a4-0a0a3ac5bc84_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_019fd2c8-7225-7a9c-8da4-ebea298ab1c5" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementScenarioAxis_019fd2c8-7225-7fad-80a4-0a0a3ac5bc84" xlink:to="loc_srt_ScenarioUnspecifiedDomain_019fd2c8-7225-7a9c-8da4-ebea298ab1c5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioForecastMember_019fd2c8-7225-74d8-8d9e-1e9c4ba6d53c" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ScenarioForecastMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_019fd2c8-7225-7a9c-8da4-ebea298ab1c5" xlink:to="loc_srt_ScenarioForecastMember_019fd2c8-7225-74d8-8d9e-1e9c4ba6d53c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_LesseeOperatingLeaseNumberOfContracts_019fd2c8-7225-75da-88fa-9e789bb4bbf8" xlink:href="glxy-20260630.xsd#glxy_LesseeOperatingLeaseNumberOfContracts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_019fd2c8-7225-763a-b671-4eecf22ebc0c" xlink:to="loc_glxy_LesseeOperatingLeaseNumberOfContracts_019fd2c8-7225-75da-88fa-9e789bb4bbf8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_VariableInterestEntityNumberOfPortfolioCompanies_019fd2c8-7225-7783-a0d8-b8e0c37fb7df" xlink:href="glxy-20260630.xsd#glxy_VariableInterestEntityNumberOfPortfolioCompanies"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_019fd2c8-7225-763a-b671-4eecf22ebc0c" xlink:to="loc_glxy_VariableInterestEntityNumberOfPortfolioCompanies_019fd2c8-7225-7783-a0d8-b8e0c37fb7df" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_VariableInterestEntityUnfundedCommitments_019fd2c8-7225-70e3-be47-ca0a45a4a60d" xlink:href="glxy-20260630.xsd#glxy_VariableInterestEntityUnfundedCommitments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_019fd2c8-7225-763a-b671-4eecf22ebc0c" xlink:to="loc_glxy_VariableInterestEntityUnfundedCommitments_019fd2c8-7225-70e3-be47-ca0a45a4a60d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_VariableInterestEntityFundingAmount_019fd2c8-7225-70da-a9e3-f3a4a04aa932" xlink:href="glxy-20260630.xsd#glxy_VariableInterestEntityFundingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_019fd2c8-7225-763a-b671-4eecf22ebc0c" xlink:to="loc_glxy_VariableInterestEntityFundingAmount_019fd2c8-7225-70da-a9e3-f3a4a04aa932" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitment_019fd2c8-7225-750b-b3a1-bf3ce41b3b2a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherCommitment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_019fd2c8-7225-763a-b671-4eecf22ebc0c" xlink:to="loc_us-gaap_OtherCommitment_019fd2c8-7225-750b-b3a1-bf3ce41b3b2a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationReserve_019fd2c8-7225-72e5-9c49-bb6dd8779b2e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LitigationReserve"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_019fd2c8-7225-763a-b671-4eecf22ebc0c" xlink:to="loc_us-gaap_LitigationReserve_019fd2c8-7225-72e5-9c49-bb6dd8779b2e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_EstimatedLitigationLiabilityDiscountRate_019fd2c8-7225-7fa0-96a5-349e78c103b7" xlink:href="glxy-20260630.xsd#glxy_EstimatedLitigationLiabilityDiscountRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_019fd2c8-7225-763a-b671-4eecf22ebc0c" xlink:to="loc_glxy_EstimatedLitigationLiabilityDiscountRate_019fd2c8-7225-7fa0-96a5-349e78c103b7" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_EstimatedLitigationLiabilityUndiscounted_019fd2c8-7225-7c49-89ac-d3aa170ac112" xlink:href="glxy-20260630.xsd#glxy_EstimatedLitigationLiabilityUndiscounted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_019fd2c8-7225-763a-b671-4eecf22ebc0c" xlink:to="loc_glxy_EstimatedLitigationLiabilityUndiscounted_019fd2c8-7225-7c49-89ac-d3aa170ac112" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForLegalSettlements_019fd2c8-7225-7712-815d-7486b28360eb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsForLegalSettlements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_019fd2c8-7225-763a-b671-4eecf22ebc0c" xlink:to="loc_us-gaap_PaymentsForLegalSettlements_019fd2c8-7225-7712-815d-7486b28360eb" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountDistributionAmount_019fd2c8-7225-7271-97d9-be93da55ad5e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LimitedPartnersCapitalAccountDistributionAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_019fd2c8-7225-763a-b671-4eecf22ebc0c" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountDistributionAmount_019fd2c8-7225-7271-97d9-be93da55ad5e" xlink:type="arc" order="9"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/LOANSANDNOTESPAYABLENarrativeDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#LOANSANDNOTESPAYABLENarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/LOANSANDNOTESPAYABLENarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7489-9a4d-f038bfd3765b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_019fd2c8-7225-7245-b963-7f10456d202c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7489-9a4d-f038bfd3765b" xlink:to="loc_us-gaap_DebtInstrumentTable_019fd2c8-7225-7245-b963-7f10456d202c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019fd2c8-7225-7ec3-b8a0-d7e877a85b84" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019fd2c8-7225-7245-b963-7f10456d202c" xlink:to="loc_us-gaap_DebtInstrumentAxis_019fd2c8-7225-7ec3-b8a0-d7e877a85b84" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019fd2c8-7225-7ec3-b8a0-d7e877a85b84_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019fd2c8-7225-7ec3-b8a0-d7e877a85b84" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019fd2c8-7225-7ec3-b8a0-d7e877a85b84_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019fd2c8-7225-7775-8998-c652d81a5c72" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019fd2c8-7225-7ec3-b8a0-d7e877a85b84" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019fd2c8-7225-7775-8998-c652d81a5c72" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_A2026ExchangeableNotesMember_019fd2c8-7225-73cf-a912-1eeab5dfb75d" xlink:href="glxy-20260630.xsd#glxy_A2026ExchangeableNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019fd2c8-7225-7775-8998-c652d81a5c72" xlink:to="loc_glxy_A2026ExchangeableNotesMember_019fd2c8-7225-73cf-a912-1eeab5dfb75d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_A2029ExchangeableNotesMember_019fd2c8-7225-7414-b5e3-0444edbda8ce" xlink:href="glxy-20260630.xsd#glxy_A2029ExchangeableNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019fd2c8-7225-7775-8998-c652d81a5c72" xlink:to="loc_glxy_A2029ExchangeableNotesMember_019fd2c8-7225-7414-b5e3-0444edbda8ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_A2031ExchangeableNotesMember_019fd2c8-7225-7af0-9c01-efa00a687a11" xlink:href="glxy-20260630.xsd#glxy_A2031ExchangeableNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019fd2c8-7225-7775-8998-c652d81a5c72" xlink:to="loc_glxy_A2031ExchangeableNotesMember_019fd2c8-7225-7af0-9c01-efa00a687a11" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_SeniorSecuredTermLoanFacilityMember_019fd2c8-7225-7821-95f3-1e4ec6c93f87" xlink:href="glxy-20260630.xsd#glxy_SeniorSecuredTermLoanFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019fd2c8-7225-7775-8998-c652d81a5c72" xlink:to="loc_glxy_SeniorSecuredTermLoanFacilityMember_019fd2c8-7225-7821-95f3-1e4ec6c93f87" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019fd2c8-7225-7947-8875-b755c1026e98" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019fd2c8-7225-7245-b963-7f10456d202c" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019fd2c8-7225-7947-8875-b755c1026e98" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019fd2c8-7225-7947-8875-b755c1026e98_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019fd2c8-7225-7947-8875-b755c1026e98" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019fd2c8-7225-7947-8875-b755c1026e98_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019fd2c8-7225-7fd8-abdf-4124c0f9318b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019fd2c8-7225-7947-8875-b755c1026e98" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019fd2c8-7225-7fd8-abdf-4124c0f9318b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_019fd2c8-7225-7586-88f9-26d3d6ce23d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019fd2c8-7225-7fd8-abdf-4124c0f9318b" xlink:to="loc_us-gaap_SeniorNotesMember_019fd2c8-7225-7586-88f9-26d3d6ce23d8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_019fd2c8-7225-74a7-9f1e-ed9607ce32bc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019fd2c8-7225-7fd8-abdf-4124c0f9318b" xlink:to="loc_us-gaap_SecuredDebtMember_019fd2c8-7225-74a7-9f1e-ed9607ce32bc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7225-7fa8-a182-4f0a610a9691" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019fd2c8-7225-7245-b963-7f10456d202c" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7225-7fa8-a182-4f0a610a9691" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019fd2c8-7225-7fa8-a182-4f0a610a9691_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7225-7fa8-a182-4f0a610a9691" xlink:to="loc_us-gaap_ClassOfStockDomain_019fd2c8-7225-7fa8-a182-4f0a610a9691_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019fd2c8-7225-730f-ba4b-ba59c9fa2d9e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7225-7fa8-a182-4f0a610a9691" xlink:to="loc_us-gaap_ClassOfStockDomain_019fd2c8-7225-730f-ba4b-ba59c9fa2d9e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_019fd2c8-7225-755d-8f5d-e2e22f2fc7de" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019fd2c8-7225-730f-ba4b-ba59c9fa2d9e" xlink:to="loc_us-gaap_CommonClassAMember_019fd2c8-7225-755d-8f5d-e2e22f2fc7de" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_019fd2c8-7225-7df1-b80a-735e1499bc96" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019fd2c8-7225-7245-b963-7f10456d202c" xlink:to="loc_us-gaap_VariableRateAxis_019fd2c8-7225-7df1-b80a-735e1499bc96" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_019fd2c8-7225-7df1-b80a-735e1499bc96_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_019fd2c8-7225-7df1-b80a-735e1499bc96" xlink:to="loc_us-gaap_VariableRateDomain_019fd2c8-7225-7df1-b80a-735e1499bc96_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_019fd2c8-7225-7125-aa78-b6b707997c8c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_019fd2c8-7225-7df1-b80a-735e1499bc96" xlink:to="loc_us-gaap_VariableRateDomain_019fd2c8-7225-7125-aa78-b6b707997c8c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_019fd2c8-7225-7dec-8ff9-58ed70a2f206" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredOvernightFinancingRateSofrMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_019fd2c8-7225-7125-aa78-b6b707997c8c" xlink:to="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_019fd2c8-7225-7dec-8ff9-58ed70a2f206" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_FloorRateMember_019fd2c8-7225-7474-a70b-97a0baaeff4d" xlink:href="glxy-20260630.xsd#glxy_FloorRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_019fd2c8-7225-7125-aa78-b6b707997c8c" xlink:to="loc_glxy_FloorRateMember_019fd2c8-7225-7474-a70b-97a0baaeff4d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseShortTermBorrowings_019fd2c8-7225-7c87-b174-ce76d5e54e50" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseShortTermBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7489-9a4d-f038bfd3765b" xlink:to="loc_us-gaap_InterestExpenseShortTermBorrowings_019fd2c8-7225-7c87-b174-ce76d5e54e50" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_019fd2c8-7225-7d17-84c4-e372896e1871" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7489-9a4d-f038bfd3765b" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_019fd2c8-7225-7d17-84c4-e372896e1871" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019fd2c8-7225-7e6d-aa5e-6980805c1bbc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7489-9a4d-f038bfd3765b" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019fd2c8-7225-7e6d-aa5e-6980805c1bbc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_019fd2c8-7225-7f94-ba62-d61bcecf9790" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7489-9a4d-f038bfd3765b" xlink:to="loc_us-gaap_CommonStockSharesIssued_019fd2c8-7225-7f94-ba62-d61bcecf9790" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_019fd2c8-7225-74c1-b7ba-d2ffb9a4e124" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7489-9a4d-f038bfd3765b" xlink:to="loc_us-gaap_CommonStockValue_019fd2c8-7225-74c1-b7ba-d2ffb9a4e124" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscount_019fd2c8-7225-7de5-9f4a-528c6021d760" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentUnamortizedDiscount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7489-9a4d-f038bfd3765b" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscount_019fd2c8-7225-7de5-9f4a-528c6021d760" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDebtIssuanceCosts_019fd2c8-7225-7974-9e5e-a91742b8df6e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsOfDebtIssuanceCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7489-9a4d-f038bfd3765b" xlink:to="loc_us-gaap_PaymentsOfDebtIssuanceCosts_019fd2c8-7225-7974-9e5e-a91742b8df6e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnamortizedDebtIssuanceExpense_019fd2c8-7225-7a71-8e9e-97d758958b91" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UnamortizedDebtIssuanceExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7489-9a4d-f038bfd3765b" xlink:to="loc_us-gaap_UnamortizedDebtIssuanceExpense_019fd2c8-7225-7a71-8e9e-97d758958b91" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDebt_019fd2c8-7225-78a5-992c-f00c15f44cd9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7489-9a4d-f038bfd3765b" xlink:to="loc_us-gaap_InterestExpenseDebt_019fd2c8-7225-78a5-992c-f00c15f44cd9" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseLongTermDebt_019fd2c8-7225-7a74-b574-86590065cd09" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseLongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7489-9a4d-f038bfd3765b" xlink:to="loc_us-gaap_InterestExpenseLongTermDebt_019fd2c8-7225-7a74-b574-86590065cd09" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_019fd2c8-7225-7519-84c5-78d2f1bcee13" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7489-9a4d-f038bfd3765b" xlink:to="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_019fd2c8-7225-7519-84c5-78d2f1bcee13" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_019fd2c8-7225-799e-99f8-cda532672211" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7489-9a4d-f038bfd3765b" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_019fd2c8-7225-799e-99f8-cda532672211" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019fd2c8-7225-70b7-996a-1f60d98e9a67" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7489-9a4d-f038bfd3765b" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019fd2c8-7225-70b7-996a-1f60d98e9a67" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestCostsIncurred_019fd2c8-7225-7568-9c22-b4f6fdd66061" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestCostsIncurred"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7489-9a4d-f038bfd3765b" xlink:to="loc_us-gaap_InterestCostsIncurred_019fd2c8-7225-7568-9c22-b4f6fdd66061" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedInterest_019fd2c8-7225-7bd0-a4f5-6360d405c35a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7489-9a4d-f038bfd3765b" xlink:to="loc_us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedInterest_019fd2c8-7225-7bd0-a4f5-6360d405c35a" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DebtInstrumentCovenantMinimumQuarterlyDebtServiceCoverageRatio_019fd2c8-7225-70b8-85cb-485162b6bd9f" xlink:href="glxy-20260630.xsd#glxy_DebtInstrumentCovenantMinimumQuarterlyDebtServiceCoverageRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7489-9a4d-f038bfd3765b" xlink:to="loc_glxy_DebtInstrumentCovenantMinimumQuarterlyDebtServiceCoverageRatio_019fd2c8-7225-70b8-85cb-485162b6bd9f" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DebtInstrumentCovenantMaximumLoanToCostRatio_019fd2c8-7225-7f5d-89fe-b745618f82fe" xlink:href="glxy-20260630.xsd#glxy_DebtInstrumentCovenantMaximumLoanToCostRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7489-9a4d-f038bfd3765b" xlink:to="loc_glxy_DebtInstrumentCovenantMaximumLoanToCostRatio_019fd2c8-7225-7f5d-89fe-b745618f82fe" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionRatio1_019fd2c8-7225-712d-aa5f-d714923711d4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentConvertibleConversionRatio1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7489-9a4d-f038bfd3765b" xlink:to="loc_us-gaap_DebtInstrumentConvertibleConversionRatio1_019fd2c8-7225-712d-aa5f-d714923711d4" xlink:type="arc" order="17"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/LOANSANDNOTESPAYABLEScheduleofRepaymentObligationDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#LOANSANDNOTESPAYABLEScheduleofRepaymentObligationDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/LOANSANDNOTESPAYABLEScheduleofRepaymentObligationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7e89-90c5-3e5f6061d0f4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_019fd2c8-7225-72f4-96f9-33cafae370e4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7e89-90c5-3e5f6061d0f4" xlink:to="loc_us-gaap_DebtInstrumentTable_019fd2c8-7225-72f4-96f9-33cafae370e4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019fd2c8-7225-76e7-9b2d-a166d35f7830" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019fd2c8-7225-72f4-96f9-33cafae370e4" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019fd2c8-7225-76e7-9b2d-a166d35f7830" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019fd2c8-7225-76e7-9b2d-a166d35f7830_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019fd2c8-7225-76e7-9b2d-a166d35f7830" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019fd2c8-7225-76e7-9b2d-a166d35f7830_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019fd2c8-7225-71bd-b5c6-09a0e3283b34" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019fd2c8-7225-76e7-9b2d-a166d35f7830" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019fd2c8-7225-71bd-b5c6-09a0e3283b34" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_019fd2c8-7225-7e6f-a705-fcb0f3d974b8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019fd2c8-7225-71bd-b5c6-09a0e3283b34" xlink:to="loc_us-gaap_SeniorNotesMember_019fd2c8-7225-7e6f-a705-fcb0f3d974b8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear_019fd2c8-7225-79cf-a053-29c976f29669" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7e89-90c5-3e5f6061d0f4" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear_019fd2c8-7225-79cf-a053-29c976f29669" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_019fd2c8-7225-76e6-b957-287f78a8f1e6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7e89-90c5-3e5f6061d0f4" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_019fd2c8-7225-76e6-b957-287f78a8f1e6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_019fd2c8-7225-7ea5-976f-93ca4e5140bc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7e89-90c5-3e5f6061d0f4" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_019fd2c8-7225-7ea5-976f-93ca4e5140bc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_019fd2c8-7225-7c5a-8605-0c2b4f8af225" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7e89-90c5-3e5f6061d0f4" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_019fd2c8-7225-7c5a-8605-0c2b4f8af225" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_019fd2c8-7225-75b0-8b1f-e7b27d6f1e78" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7e89-90c5-3e5f6061d0f4" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_019fd2c8-7225-75b0-8b1f-e7b27d6f1e78" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive_019fd2c8-7225-7c03-a0ff-ba3644b432b8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7e89-90c5-3e5f6061d0f4" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive_019fd2c8-7225-7c03-a0ff-ba3644b432b8" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_019fd2c8-7225-7165-9aa8-ca48b650fb7a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019fd2c8-7225-7e89-90c5-3e5f6061d0f4" xlink:to="loc_us-gaap_LongTermDebt_019fd2c8-7225-7165-9aa8-ca48b650fb7a" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/EQUITYDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#EQUITYDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/EQUITYDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_019fd2c8-7225-7a30-ac31-03dbe2fd0b54" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_019fd2c8-7225-7406-8328-1cf5b5b8b3b2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_019fd2c8-7225-7a30-ac31-03dbe2fd0b54" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_019fd2c8-7225-7406-8328-1cf5b5b8b3b2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7225-7519-a665-e8ee359d2edc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_019fd2c8-7225-7406-8328-1cf5b5b8b3b2" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7225-7519-a665-e8ee359d2edc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019fd2c8-7225-7519-a665-e8ee359d2edc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7225-7519-a665-e8ee359d2edc" xlink:to="loc_us-gaap_ClassOfStockDomain_019fd2c8-7225-7519-a665-e8ee359d2edc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019fd2c8-7225-7f96-8d41-db12216e7f01" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7225-7519-a665-e8ee359d2edc" xlink:to="loc_us-gaap_ClassOfStockDomain_019fd2c8-7225-7f96-8d41-db12216e7f01" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassBMember_019fd2c8-7225-7180-ba92-4776f0b27817" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonClassBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019fd2c8-7225-7f96-8d41-db12216e7f01" xlink:to="loc_us-gaap_CommonClassBMember_019fd2c8-7225-7180-ba92-4776f0b27817" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_PartnershipUnitExchangeRatio_019fd2c8-7225-7e6f-a7fc-d69b5bb868fc" xlink:href="glxy-20260630.xsd#glxy_PartnershipUnitExchangeRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019fd2c8-7225-7a30-ac31-03dbe2fd0b54" xlink:to="loc_glxy_PartnershipUnitExchangeRatio_019fd2c8-7225-7e6f-a7fc-d69b5bb868fc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_019fd2c8-7225-7368-807e-181fed74acd9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019fd2c8-7225-7a30-ac31-03dbe2fd0b54" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_019fd2c8-7225-7368-807e-181fed74acd9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountDistributionAmount_019fd2c8-7225-78be-b5c0-db15d8256d06" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LimitedPartnersCapitalAccountDistributionAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019fd2c8-7225-7a30-ac31-03dbe2fd0b54" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountDistributionAmount_019fd2c8-7225-78be-b5c0-db15d8256d06" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/EARNINGSPERSHAREScheduleofEarningsPerShareBasicandDilutedDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#EARNINGSPERSHAREScheduleofEarningsPerShareBasicandDilutedDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/EARNINGSPERSHAREScheduleofEarningsPerShareBasicandDilutedDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_019fd2c8-7225-7360-b1fd-3749025ecfe8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_019fd2c8-7225-7104-860b-887278d256b5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_019fd2c8-7225-7360-b1fd-3749025ecfe8" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_019fd2c8-7225-7104-860b-887278d256b5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7225-7c02-a218-166371058a30" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_019fd2c8-7225-7104-860b-887278d256b5" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7225-7c02-a218-166371058a30" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019fd2c8-7225-7c02-a218-166371058a30_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7225-7c02-a218-166371058a30" xlink:to="loc_us-gaap_ClassOfStockDomain_019fd2c8-7225-7c02-a218-166371058a30_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019fd2c8-7225-74d1-9456-3de86a63d4c7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7225-7c02-a218-166371058a30" xlink:to="loc_us-gaap_ClassOfStockDomain_019fd2c8-7225-74d1-9456-3de86a63d4c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_019fd2c8-7225-72d5-88ce-b21aee9a8ed7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019fd2c8-7225-74d1-9456-3de86a63d4c7" xlink:to="loc_us-gaap_CommonClassAMember_019fd2c8-7225-72d5-88ce-b21aee9a8ed7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasicAbstract_019fd2c8-7225-7947-ba01-0b137ac174a9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareBasicAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019fd2c8-7225-7360-b1fd-3749025ecfe8" xlink:to="loc_us-gaap_EarningsPerShareBasicAbstract_019fd2c8-7225-7947-ba01-0b137ac174a9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_019fd2c8-7225-703b-bef5-7a72cb6b80c2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAbstract_019fd2c8-7225-7947-ba01-0b137ac174a9" xlink:to="loc_us-gaap_EarningsPerShareBasic_019fd2c8-7225-703b-bef5-7a72cb6b80c2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019fd2c8-7225-7843-9918-892120204bd4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAbstract_019fd2c8-7225-7947-ba01-0b137ac174a9" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019fd2c8-7225-7843-9918-892120204bd4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019fd2c8-7225-733e-9fa4-00814fe421d9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAbstract_019fd2c8-7225-7947-ba01-0b137ac174a9" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019fd2c8-7225-733e-9fa4-00814fe421d9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDilutedAbstract_019fd2c8-7225-7909-91ef-c00c3200f044" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareDilutedAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019fd2c8-7225-7360-b1fd-3749025ecfe8" xlink:to="loc_us-gaap_EarningsPerShareDilutedAbstract_019fd2c8-7225-7909-91ef-c00c3200f044" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_019fd2c8-7225-7bfe-b4e3-e488f36d70f3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareDilutedAbstract_019fd2c8-7225-7909-91ef-c00c3200f044" xlink:to="loc_us-gaap_EarningsPerShareDiluted_019fd2c8-7225-7bfe-b4e3-e488f36d70f3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_019fd2c8-7225-7115-a896-ccf9b188dbd9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareDilutedAbstract_019fd2c8-7225-7909-91ef-c00c3200f044" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_019fd2c8-7225-7115-a896-ccf9b188dbd9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019fd2c8-7225-7f9f-9424-557b2c4c81de" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareDilutedAbstract_019fd2c8-7225-7909-91ef-c00c3200f044" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019fd2c8-7225-7f9f-9424-557b2c4c81de" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/EARNINGSPERSHAREScheduleofAdjustmentsBasicIncomeLossperShareDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#EARNINGSPERSHAREScheduleofAdjustmentsBasicIncomeLossperShareDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/EARNINGSPERSHAREScheduleofAdjustmentsBasicIncomeLossperShareDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDilutedLineItems_019fd2c8-7226-77bf-bc35-062e543f4cda" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareDilutedLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEarningsPerShareDilutedByCommonClassTable_019fd2c8-7226-7aba-bc8a-875342546a76" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfEarningsPerShareDilutedByCommonClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EarningsPerShareDilutedLineItems_019fd2c8-7226-77bf-bc35-062e543f4cda" xlink:to="loc_us-gaap_ScheduleOfEarningsPerShareDilutedByCommonClassTable_019fd2c8-7226-7aba-bc8a-875342546a76" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7226-793d-a7a3-a879ddad1654" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEarningsPerShareDilutedByCommonClassTable_019fd2c8-7226-7aba-bc8a-875342546a76" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7226-793d-a7a3-a879ddad1654" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019fd2c8-7226-793d-a7a3-a879ddad1654_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7226-793d-a7a3-a879ddad1654" xlink:to="loc_us-gaap_ClassOfStockDomain_019fd2c8-7226-793d-a7a3-a879ddad1654_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019fd2c8-7226-79b0-9b05-107289ed64aa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019fd2c8-7226-793d-a7a3-a879ddad1654" xlink:to="loc_us-gaap_ClassOfStockDomain_019fd2c8-7226-79b0-9b05-107289ed64aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_NoncontrollingInterestUnitsMember_019fd2c8-7226-71cb-b02d-96b876b08440" xlink:href="glxy-20260630.xsd#glxy_NoncontrollingInterestUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019fd2c8-7226-79b0-9b05-107289ed64aa" xlink:to="loc_glxy_NoncontrollingInterestUnitsMember_019fd2c8-7226-71cb-b02d-96b876b08440" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CompensatoryAwardsMember_019fd2c8-7226-7f5a-a7c8-759c8455f446" xlink:href="glxy-20260630.xsd#glxy_CompensatoryAwardsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019fd2c8-7226-79b0-9b05-107289ed64aa" xlink:to="loc_glxy_CompensatoryAwardsMember_019fd2c8-7226-7f5a-a7c8-759c8455f446" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019fd2c8-7226-7eb0-93a2-b460eb00d9a5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareDilutedLineItems_019fd2c8-7226-77bf-bc35-062e543f4cda" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019fd2c8-7226-7eb0-93a2-b460eb00d9a5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_019fd2c8-7226-769e-81f7-63e3ae1146eb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareDilutedLineItems_019fd2c8-7226-77bf-bc35-062e543f4cda" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_019fd2c8-7226-769e-81f7-63e3ae1146eb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_019fd2c8-7226-7780-b907-7fc6c546ea6c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareDilutedLineItems_019fd2c8-7226-77bf-bc35-062e543f4cda" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_019fd2c8-7226-7780-b907-7fc6c546ea6c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019fd2c8-7226-7ff1-92a9-3375b5ec2f5a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareDilutedLineItems_019fd2c8-7226-77bf-bc35-062e543f4cda" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019fd2c8-7226-7ff1-92a9-3375b5ec2f5a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_019fd2c8-7226-7d6a-99ed-b60eb4ae33b4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareDilutedLineItems_019fd2c8-7226-77bf-bc35-062e543f4cda" xlink:to="loc_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_019fd2c8-7226-7d6a-99ed-b60eb4ae33b4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019fd2c8-7226-7d90-b66c-add945792d0e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareDilutedLineItems_019fd2c8-7226-77bf-bc35-062e543f4cda" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019fd2c8-7226-7d90-b66c-add945792d0e" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/EARNINGSPERSHAREScheduleofAntidilutiveSecuritiesExcludedfromComputationofEarningsPerShareDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#EARNINGSPERSHAREScheduleofAntidilutiveSecuritiesExcludedfromComputationofEarningsPerShareDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/EARNINGSPERSHAREScheduleofAntidilutiveSecuritiesExcludedfromComputationofEarningsPerShareDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_019fd2c8-7226-797d-a2e7-fedb56223c81" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_019fd2c8-7226-7129-8c0e-d8cfb9b2666b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_019fd2c8-7226-797d-a2e7-fedb56223c81" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_019fd2c8-7226-7129-8c0e-d8cfb9b2666b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019fd2c8-7226-7754-a788-a2a7dd3b764c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_019fd2c8-7226-7129-8c0e-d8cfb9b2666b" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019fd2c8-7226-7754-a788-a2a7dd3b764c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019fd2c8-7226-7754-a788-a2a7dd3b764c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019fd2c8-7226-7754-a788-a2a7dd3b764c" xlink:to="loc_us-gaap_EquityComponentDomain_019fd2c8-7226-7754-a788-a2a7dd3b764c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019fd2c8-7226-7bc0-8023-ab8ebc4f6444" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019fd2c8-7226-7754-a788-a2a7dd3b764c" xlink:to="loc_us-gaap_EquityComponentDomain_019fd2c8-7226-7bc0-8023-ab8ebc4f6444" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_ExchangeableLPUnitsMember_019fd2c8-7226-73b9-823f-b03c8f267e74" xlink:href="glxy-20260630.xsd#glxy_ExchangeableLPUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019fd2c8-7226-7bc0-8023-ab8ebc4f6444" xlink:to="loc_glxy_ExchangeableLPUnitsMember_019fd2c8-7226-73b9-823f-b03c8f267e74" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CompensatoryAwardsMember_019fd2c8-7226-7f24-9ce6-7391be5c0286" xlink:href="glxy-20260630.xsd#glxy_CompensatoryAwardsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019fd2c8-7226-7bc0-8023-ab8ebc4f6444" xlink:to="loc_glxy_CompensatoryAwardsMember_019fd2c8-7226-7f24-9ce6-7391be5c0286" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_ExchangeableNotesMember_019fd2c8-7226-7e7a-88c1-a27f4944fb9d" xlink:href="glxy-20260630.xsd#glxy_ExchangeableNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019fd2c8-7226-7bc0-8023-ab8ebc4f6444" xlink:to="loc_glxy_ExchangeableNotesMember_019fd2c8-7226-7e7a-88c1-a27f4944fb9d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_019fd2c8-7226-7410-ad24-3db603b5dab7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019fd2c8-7226-797d-a2e7-fedb56223c81" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_019fd2c8-7226-7410-ad24-3db603b5dab7" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/RELATEDPARTYTRANSACTIONSDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#RELATEDPARTYTRANSACTIONSDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/RELATEDPARTYTRANSACTIONSDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_019fd2c8-7226-7c2a-a601-0ec2bd6a1b3f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019fd2c8-7226-799c-b083-666622a720f6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019fd2c8-7226-7c2a-a601-0ec2bd6a1b3f" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019fd2c8-7226-799c-b083-666622a720f6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_019fd2c8-7226-7ad0-ac6a-1cba074aa68e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019fd2c8-7226-799c-b083-666622a720f6" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_019fd2c8-7226-7ad0-ac6a-1cba074aa68e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_019fd2c8-7226-7ad0-ac6a-1cba074aa68e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_019fd2c8-7226-7ad0-ac6a-1cba074aa68e" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_019fd2c8-7226-7ad0-ac6a-1cba074aa68e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_019fd2c8-7226-789f-8bad-d5fb44a5be72" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_019fd2c8-7226-7ad0-ac6a-1cba074aa68e" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_019fd2c8-7226-789f-8bad-d5fb44a5be72" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_TaxReceivableAgreementMember_019fd2c8-7226-7912-baae-f385e5e59644" xlink:href="glxy-20260630.xsd#glxy_TaxReceivableAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_019fd2c8-7226-789f-8bad-d5fb44a5be72" xlink:to="loc_glxy_TaxReceivableAgreementMember_019fd2c8-7226-7912-baae-f385e5e59644" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019fd2c8-7226-7718-9c9d-06ce6305dbed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019fd2c8-7226-799c-b083-666622a720f6" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019fd2c8-7226-7718-9c9d-06ce6305dbed" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019fd2c8-7226-7718-9c9d-06ce6305dbed_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019fd2c8-7226-7718-9c9d-06ce6305dbed" xlink:to="loc_us-gaap_RelatedPartyDomain_019fd2c8-7226-7718-9c9d-06ce6305dbed_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019fd2c8-7226-72cd-8a92-c49adaa5b535" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019fd2c8-7226-7718-9c9d-06ce6305dbed" xlink:to="loc_us-gaap_RelatedPartyDomain_019fd2c8-7226-72cd-8a92-c49adaa5b535" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019fd2c8-7226-7479-a03f-80d8e78941f5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019fd2c8-7226-72cd-8a92-c49adaa5b535" xlink:to="loc_us-gaap_RelatedPartyMember_019fd2c8-7226-7479-a03f-80d8e78941f5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_019fd2c8-7226-7794-bf51-bf4945fbe6ce" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019fd2c8-7226-799c-b083-666622a720f6" xlink:to="loc_dei_LegalEntityAxis_019fd2c8-7226-7794-bf51-bf4945fbe6ce" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019fd2c8-7226-7794-bf51-bf4945fbe6ce_default" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_019fd2c8-7226-7794-bf51-bf4945fbe6ce" xlink:to="loc_dei_EntityDomain_019fd2c8-7226-7794-bf51-bf4945fbe6ce_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019fd2c8-7226-78f2-9a18-fc2df2d445fe" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_019fd2c8-7226-7794-bf51-bf4945fbe6ce" xlink:to="loc_dei_EntityDomain_019fd2c8-7226-78f2-9a18-fc2df2d445fe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_GalaxyDigitalHoldingsLPMember_019fd2c8-7226-71c3-baff-4aab3d844fdc" xlink:href="glxy-20260630.xsd#glxy_GalaxyDigitalHoldingsLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_019fd2c8-7226-78f2-9a18-fc2df2d445fe" xlink:to="loc_glxy_GalaxyDigitalHoldingsLPMember_019fd2c8-7226-71c3-baff-4aab3d844fdc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountDistributionAmount_019fd2c8-7226-7143-acd1-db110374d793" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LimitedPartnersCapitalAccountDistributionAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019fd2c8-7226-7c2a-a601-0ec2bd6a1b3f" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountDistributionAmount_019fd2c8-7226-7143-acd1-db110374d793" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionRate_019fd2c8-7226-7609-ae14-39dafb5e9810" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019fd2c8-7226-7c2a-a601-0ec2bd6a1b3f" xlink:to="loc_us-gaap_RelatedPartyTransactionRate_019fd2c8-7226-7609-ae14-39dafb5e9810" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_TaxReceivableAgreementLiabilityNoncurrent_019fd2c8-7226-766c-8216-be634c31d4d3" xlink:href="glxy-20260630.xsd#glxy_TaxReceivableAgreementLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019fd2c8-7226-7c2a-a601-0ec2bd6a1b3f" xlink:to="loc_glxy_TaxReceivableAgreementLiabilityNoncurrent_019fd2c8-7226-766c-8216-be634c31d4d3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_ReceivableAgreementLiabilityNoncurrent_019fd2c8-7226-7817-8513-ab92999da307" xlink:href="glxy-20260630.xsd#glxy_ReceivableAgreementLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019fd2c8-7226-7c2a-a601-0ec2bd6a1b3f" xlink:to="loc_glxy_ReceivableAgreementLiabilityNoncurrent_019fd2c8-7226-7817-8513-ab92999da307" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentOwnedAtFairValue_019fd2c8-7226-7147-bce5-489801e7ddce" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentOwnedAtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019fd2c8-7226-7c2a-a601-0ec2bd6a1b3f" xlink:to="loc_us-gaap_InvestmentOwnedAtFairValue_019fd2c8-7226-7147-bce5-489801e7ddce" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_019fd2c8-7226-7111-9623-2e475eabf09f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019fd2c8-7226-7c2a-a601-0ec2bd6a1b3f" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_019fd2c8-7226-7111-9623-2e475eabf09f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_019fd2c8-7226-7413-b944-204d84ef101a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019fd2c8-7226-7c2a-a601-0ec2bd6a1b3f" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_019fd2c8-7226-7413-b944-204d84ef101a" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_RelatedPartyPayables_019fd2c8-7226-71cb-afff-e519014177aa" xlink:href="glxy-20260630.xsd#glxy_RelatedPartyPayables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019fd2c8-7226-7c2a-a601-0ec2bd6a1b3f" xlink:to="loc_glxy_RelatedPartyPayables_019fd2c8-7226-71cb-afff-e519014177aa" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestExpenseInvestmentAdvisoryFees_019fd2c8-7226-7328-8116-03c2282b3162" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoninterestExpenseInvestmentAdvisoryFees"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019fd2c8-7226-7c2a-a601-0ec2bd6a1b3f" xlink:to="loc_us-gaap_NoninterestExpenseInvestmentAdvisoryFees_019fd2c8-7226-7328-8116-03c2282b3162" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_UseOfAircraftExpense_019fd2c8-7226-7e9c-9122-f7c4c05cdf76" xlink:href="glxy-20260630.xsd#glxy_UseOfAircraftExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019fd2c8-7226-7c2a-a601-0ec2bd6a1b3f" xlink:to="loc_glxy_UseOfAircraftExpense_019fd2c8-7226-7e9c-9122-f7c4c05cdf76" xlink:type="arc" order="9"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/REPORTABLESEGMENTSScheduleofAssetsandLiabilitiesbyReportableSegmentDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#REPORTABLESEGMENTSScheduleofAssetsandLiabilitiesbyReportableSegmentDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/REPORTABLESEGMENTSScheduleofAssetsandLiabilitiesbyReportableSegmentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-7b06-b96b-972ece5d7b8f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019fd2c8-7226-7601-877c-f76b06ee8293" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-7b06-b96b-972ece5d7b8f" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019fd2c8-7226-7601-877c-f76b06ee8293" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019fd2c8-7226-7e5a-b876-168b8d10becf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019fd2c8-7226-7601-877c-f76b06ee8293" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019fd2c8-7226-7e5a-b876-168b8d10becf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019fd2c8-7226-7e5a-b876-168b8d10becf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019fd2c8-7226-7e5a-b876-168b8d10becf" xlink:to="loc_us-gaap_SegmentDomain_019fd2c8-7226-7e5a-b876-168b8d10becf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019fd2c8-7226-7d9b-9c68-806173397bbd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019fd2c8-7226-7e5a-b876-168b8d10becf" xlink:to="loc_us-gaap_SegmentDomain_019fd2c8-7226-7d9b-9c68-806173397bbd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DigitalAssetsMember_019fd2c8-7226-7af3-897d-e8e2a2d6b6e0" xlink:href="glxy-20260630.xsd#glxy_DigitalAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fd2c8-7226-7d9b-9c68-806173397bbd" xlink:to="loc_glxy_DigitalAssetsMember_019fd2c8-7226-7af3-897d-e8e2a2d6b6e0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DataCentersMember_019fd2c8-72f3-7771-854c-2c315dbd6cfe" xlink:href="glxy-20260630.xsd#glxy_DataCentersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fd2c8-7226-7d9b-9c68-806173397bbd" xlink:to="loc_glxy_DataCentersMember_019fd2c8-72f3-7771-854c-2c315dbd6cfe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_TreasuryAndCorporateMember_019fd2c8-72f3-72f8-8957-35444263fef7" xlink:href="glxy-20260630.xsd#glxy_TreasuryAndCorporateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fd2c8-7226-7d9b-9c68-806173397bbd" xlink:to="loc_glxy_TreasuryAndCorporateMember_019fd2c8-72f3-72f8-8957-35444263fef7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_019fd2c8-72f3-7214-87df-1420b69e6105" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-7b06-b96b-972ece5d7b8f" xlink:to="loc_us-gaap_Assets_019fd2c8-72f3-7214-87df-1420b69e6105" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_019fd2c8-72f3-7cd9-8bc2-f5a83e36c4e9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Liabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-7b06-b96b-972ece5d7b8f" xlink:to="loc_us-gaap_Liabilities_019fd2c8-72f3-7cd9-8bc2-f5a83e36c4e9" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/REPORTABLESEGMENTSScheduleIncomeandExpensesbyReportableSegmentDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#REPORTABLESEGMENTSScheduleIncomeandExpensesbyReportableSegmentDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/REPORTABLESEGMENTSScheduleIncomeandExpensesbyReportableSegmentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019fd2c8-72f3-768a-8210-e24991d478ac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019fd2c8-72f3-768a-8210-e24991d478ac" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_019fd2c8-72f3-77e0-80f9-366b1d6001fb" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019fd2c8-72f3-768a-8210-e24991d478ac" xlink:to="loc_srt_ConsolidationItemsAxis_019fd2c8-72f3-77e0-80f9-366b1d6001fb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019fd2c8-72f3-77e0-80f9-366b1d6001fb_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_019fd2c8-72f3-77e0-80f9-366b1d6001fb" xlink:to="loc_srt_ConsolidationItemsDomain_019fd2c8-72f3-77e0-80f9-366b1d6001fb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019fd2c8-72f3-72f9-8890-c9d952acc342" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_019fd2c8-72f3-77e0-80f9-366b1d6001fb" xlink:to="loc_srt_ConsolidationItemsDomain_019fd2c8-72f3-72f9-8890-c9d952acc342" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_019fd2c8-72f3-7f21-b148-455f7d267ced" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019fd2c8-72f3-72f9-8890-c9d952acc342" xlink:to="loc_us-gaap_OperatingSegmentsMember_019fd2c8-72f3-7f21-b148-455f7d267ced" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019fd2c8-72f3-7fed-be5c-cf260753b114" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019fd2c8-72f3-768a-8210-e24991d478ac" xlink:to="loc_srt_ProductOrServiceAxis_019fd2c8-72f3-7fed-be5c-cf260753b114" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019fd2c8-72f3-7fed-be5c-cf260753b114_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019fd2c8-72f3-7fed-be5c-cf260753b114" xlink:to="loc_srt_ProductsAndServicesDomain_019fd2c8-72f3-7fed-be5c-cf260753b114_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019fd2c8-72f3-7038-a004-ed916d5ed46a" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019fd2c8-72f3-7fed-be5c-cf260753b114" xlink:to="loc_srt_ProductsAndServicesDomain_019fd2c8-72f3-7038-a004-ed916d5ed46a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DigitalAssetsSalesMember_019fd2c8-72f3-7144-a114-20ebe7f3ea02" xlink:href="glxy-20260630.xsd#glxy_DigitalAssetsSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019fd2c8-72f3-7038-a004-ed916d5ed46a" xlink:to="loc_glxy_DigitalAssetsSalesMember_019fd2c8-72f3-7144-a114-20ebe7f3ea02" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_FeeMember_019fd2c8-72f3-7b6a-87c7-a2cafb208bb2" xlink:href="glxy-20260630.xsd#glxy_FeeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019fd2c8-72f3-7038-a004-ed916d5ed46a" xlink:to="loc_glxy_FeeMember_019fd2c8-72f3-7b6a-87c7-a2cafb208bb2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_BlockchainRewardsMember_019fd2c8-72f3-7a96-96a3-88b7c6aafd03" xlink:href="glxy-20260630.xsd#glxy_BlockchainRewardsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019fd2c8-72f3-7038-a004-ed916d5ed46a" xlink:to="loc_glxy_BlockchainRewardsMember_019fd2c8-72f3-7a96-96a3-88b7c6aafd03" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_ProprietaryMiningMember_019fd2c8-72f3-769b-be29-785e9e8c26df" xlink:href="glxy-20260630.xsd#glxy_ProprietaryMiningMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019fd2c8-72f3-7038-a004-ed916d5ed46a" xlink:to="loc_glxy_ProprietaryMiningMember_019fd2c8-72f3-769b-be29-785e9e8c26df" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_BlockchainRewardsFromNonCustomersMember_019fd2c8-72f3-7562-b959-c3d0249c3da0" xlink:href="glxy-20260630.xsd#glxy_BlockchainRewardsFromNonCustomersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019fd2c8-72f3-7038-a004-ed916d5ed46a" xlink:to="loc_glxy_BlockchainRewardsFromNonCustomersMember_019fd2c8-72f3-7562-b959-c3d0249c3da0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019fd2c8-72f3-7f47-9d0f-0e6424662d2f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019fd2c8-72f3-768a-8210-e24991d478ac" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019fd2c8-72f3-7f47-9d0f-0e6424662d2f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019fd2c8-72f3-7f47-9d0f-0e6424662d2f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019fd2c8-72f3-7f47-9d0f-0e6424662d2f" xlink:to="loc_us-gaap_SegmentDomain_019fd2c8-72f3-7f47-9d0f-0e6424662d2f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019fd2c8-72f3-73b0-a0bd-80539696fbd3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019fd2c8-72f3-7f47-9d0f-0e6424662d2f" xlink:to="loc_us-gaap_SegmentDomain_019fd2c8-72f3-73b0-a0bd-80539696fbd3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DigitalAssetsMember_019fd2c8-72f3-7954-ae81-0dee9ff6b9d1" xlink:href="glxy-20260630.xsd#glxy_DigitalAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fd2c8-72f3-73b0-a0bd-80539696fbd3" xlink:to="loc_glxy_DigitalAssetsMember_019fd2c8-72f3-7954-ae81-0dee9ff6b9d1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DataCentersMember_019fd2c8-72f3-7e3b-860b-61a03dd8ce58" xlink:href="glxy-20260630.xsd#glxy_DataCentersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fd2c8-72f3-73b0-a0bd-80539696fbd3" xlink:to="loc_glxy_DataCentersMember_019fd2c8-72f3-7e3b-860b-61a03dd8ce58" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_TreasuryAndCorporateMember_019fd2c8-72f3-7e0a-acc2-26f5b973eb8e" xlink:href="glxy-20260630.xsd#glxy_TreasuryAndCorporateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019fd2c8-72f3-73b0-a0bd-80539696fbd3" xlink:to="loc_glxy_TreasuryAndCorporateMember_019fd2c8-72f3-7e0a-acc2-26f5b973eb8e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019fd2c8-72f3-70d4-ac84-0eeba2787249" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019fd2c8-72f3-70d4-ac84-0eeba2787249" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueNotFromContractWithCustomer_019fd2c8-72f3-7e55-95a2-675779b09889" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueNotFromContractWithCustomer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_us-gaap_RevenueNotFromContractWithCustomer_019fd2c8-72f3-7e55-95a2-675779b09889" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIncomeInterest_019fd2c8-72f3-71a0-b32d-14aa68032a62" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentIncomeInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_us-gaap_InvestmentIncomeInterest_019fd2c8-72f3-71a0-b32d-14aa68032a62" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DataCentersOperatorRevenue_019fd2c8-72f3-7e70-85ea-9be4ad0378a9" xlink:href="glxy-20260630.xsd#glxy_DataCentersOperatorRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_glxy_DataCentersOperatorRevenue_019fd2c8-72f3-7e70-85ea-9be4ad0378a9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_019fd2c8-72f3-7889-bf5a-6475df6e5aff" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_us-gaap_Revenues_019fd2c8-72f3-7889-bf5a-6475df6e5aff" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_GainsLossesFromOperations_019fd2c8-72f3-7715-ae82-40ca7e9396f4" xlink:href="glxy-20260630.xsd#glxy_GainsLossesFromOperations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_glxy_GainsLossesFromOperations_019fd2c8-72f3-7715-ae82-40ca7e9396f4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DataCentersLeasingRevenue_019fd2c8-72f3-7e24-b084-a885dd8f15ab" xlink:href="glxy-20260630.xsd#glxy_DataCentersLeasingRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_glxy_DataCentersLeasingRevenue_019fd2c8-72f3-7e24-b084-a885dd8f15ab" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_RevenuesAndGainsLossesFromOperations_019fd2c8-72f3-7002-8cd2-20810e164d43" xlink:href="glxy-20260630.xsd#glxy_RevenuesAndGainsLossesFromOperations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_glxy_RevenuesAndGainsLossesFromOperations_019fd2c8-72f3-7002-8cd2-20810e164d43" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingExpense_019fd2c8-72f3-7f83-af8a-04ea09178f15" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SellingExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_us-gaap_SellingExpense_019fd2c8-72f3-7f83-af8a-04ea09178f15" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetBlockchainRewardDistributionsExpense_019fd2c8-72f3-7573-8fa6-621b1479dfb9" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetBlockchainRewardDistributionsExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_glxy_CryptoAssetBlockchainRewardDistributionsExpense_019fd2c8-72f3-7573-8fa6-621b1479dfb9" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_BorrowingCosts_019fd2c8-72f3-79fe-a77f-487d0e9ed84e" xlink:href="glxy-20260630.xsd#glxy_BorrowingCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_glxy_BorrowingCosts_019fd2c8-72f3-79fe-a77f-487d0e9ed84e" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetsMiningAndHostingCosts_019fd2c8-72f3-77a2-850e-37c2035022a5" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetsMiningAndHostingCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_glxy_CryptoAssetsMiningAndHostingCosts_019fd2c8-72f3-77a2-850e-37c2035022a5" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_OtherTransactionExpenses_019fd2c8-72f3-7d3b-a16f-422417b0a537" xlink:href="glxy-20260630.xsd#glxy_OtherTransactionExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_glxy_OtherTransactionExpenses_019fd2c8-72f3-7d3b-a16f-422417b0a537" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_DataCentersOperatingCost_019fd2c8-72f3-78c3-a072-f31cf2515c9d" xlink:href="glxy-20260630.xsd#glxy_DataCentersOperatingCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_glxy_DataCentersOperatingCost_019fd2c8-72f3-78c3-a072-f31cf2515c9d" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_TransactionExpenses_019fd2c8-72f3-7cd7-a450-40e513b80046" xlink:href="glxy-20260630.xsd#glxy_TransactionExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_glxy_TransactionExpenses_019fd2c8-72f3-7cd7-a450-40e513b80046" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetImpairmentCharges_019fd2c8-72f3-7f4a-a025-ad9f4b4148b0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetImpairmentCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_us-gaap_AssetImpairmentCharges_019fd2c8-72f3-7f4a-a025-ad9f4b4148b0" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LaborAndRelatedExpense_019fd2c8-72f3-72c2-b89d-e0e9aed63332" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LaborAndRelatedExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_us-gaap_LaborAndRelatedExpense_019fd2c8-72f3-72c2-b89d-e0e9aed63332" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseMediumTermNotes_019fd2c8-72f3-75b2-aa40-78958d000796" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseMediumTermNotes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_us-gaap_InterestExpenseMediumTermNotes_019fd2c8-72f3-75b2-aa40-78958d000796" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_019fd2c8-72f3-79a5-b5a5-a33b65c1ec4e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_019fd2c8-72f3-79a5-b5a5-a33b65c1ec4e" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingOtherItemAmount_019fd2c8-72f3-7302-93fd-08d756310804" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingOtherItemAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_us-gaap_SegmentReportingOtherItemAmount_019fd2c8-72f3-7302-93fd-08d756310804" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenses_019fd2c8-72f3-7176-b137-2186f3ec5530" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_us-gaap_OperatingExpenses_019fd2c8-72f3-7176-b137-2186f3ec5530" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrealizedGainLossOnDerivatives_019fd2c8-72f3-782b-8f4c-1ac97ef3b6ac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UnrealizedGainLossOnDerivatives"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_us-gaap_UnrealizedGainLossOnDerivatives_019fd2c8-72f3-782b-8f4c-1ac97ef3b6ac" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_019fd2c8-72f3-7101-90ef-34f6afd18422" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_019fd2c8-72f3-7101-90ef-34f6afd18422" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_019fd2c8-72f3-7111-9fe5-c6e18922081b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_019fd2c8-72f3-7111-9fe5-c6e18922081b" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019fd2c8-72f3-7d95-998c-4e40c15d1c15" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019fd2c8-72f3-7d95-998c-4e40c15d1c15" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_019fd2c8-72f3-714d-99f9-1191cac6c943" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_019fd2c8-72f3-714d-99f9-1191cac6c943" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019fd2c8-72f3-7ff6-8592-c337814d828b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019fd2c8-72f3-72d8-a64d-554843797eca" xlink:to="loc_us-gaap_NetIncomeLoss_019fd2c8-72f3-7ff6-8592-c337814d828b" xlink:type="arc" order="26"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/RISKSANDUNCERTAINTIESDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#RISKSANDUNCERTAINTIESDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/RISKSANDUNCERTAINTIESDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskLineItems_019fd2c8-72f3-78cb-962d-9a38878c930b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTable_019fd2c8-72f3-76cb-8ed0-e8933c154e0a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_019fd2c8-72f3-78cb-962d-9a38878c930b" xlink:to="loc_us-gaap_ConcentrationRiskTable_019fd2c8-72f3-76cb-8ed0-e8933c154e0a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CryptoAssetAxis_019fd2c8-72f3-722c-9070-a28c661cf5ee" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CryptoAssetAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_019fd2c8-72f3-76cb-8ed0-e8933c154e0a" xlink:to="loc_srt_CryptoAssetAxis_019fd2c8-72f3-722c-9070-a28c661cf5ee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CryptoAssetDomain_019fd2c8-72f3-722c-9070-a28c661cf5ee_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CryptoAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CryptoAssetAxis_019fd2c8-72f3-722c-9070-a28c661cf5ee" xlink:to="loc_srt_CryptoAssetDomain_019fd2c8-72f3-722c-9070-a28c661cf5ee_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CryptoAssetDomain_019fd2c8-72f3-71e1-a948-db642ee680e6" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CryptoAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CryptoAssetAxis_019fd2c8-72f3-722c-9070-a28c661cf5ee" xlink:to="loc_srt_CryptoAssetDomain_019fd2c8-72f3-71e1-a948-db642ee680e6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_ThreeProtocolsMember_019fd2c8-72f3-7c6a-9268-34d1d2014b7c" xlink:href="glxy-20260630.xsd#glxy_ThreeProtocolsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CryptoAssetDomain_019fd2c8-72f3-71e1-a948-db642ee680e6" xlink:to="loc_glxy_ThreeProtocolsMember_019fd2c8-72f3-7c6a-9268-34d1d2014b7c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019fd2c8-72f3-7c6b-b54d-b3203605fca3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_019fd2c8-72f3-76cb-8ed0-e8933c154e0a" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019fd2c8-72f3-7c6b-b54d-b3203605fca3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019fd2c8-72f3-7c6b-b54d-b3203605fca3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019fd2c8-72f3-7c6b-b54d-b3203605fca3" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019fd2c8-72f3-7c6b-b54d-b3203605fca3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019fd2c8-72f3-7591-a482-b90d2f735ff8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019fd2c8-72f3-7c6b-b54d-b3203605fca3" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019fd2c8-72f3-7591-a482-b90d2f735ff8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetDecentralizedFinanceProtocolsMember_019fd2c8-72f3-7c65-bf6f-6dd115d6a958" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetDecentralizedFinanceProtocolsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019fd2c8-72f3-7591-a482-b90d2f735ff8" xlink:to="loc_glxy_CryptoAssetDecentralizedFinanceProtocolsMember_019fd2c8-72f3-7c65-bf6f-6dd115d6a958" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesRevenueNetMember_019fd2c8-72f3-792d-a24e-48a3c4d9fab7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SalesRevenueNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019fd2c8-72f3-7591-a482-b90d2f735ff8" xlink:to="loc_us-gaap_SalesRevenueNetMember_019fd2c8-72f3-792d-a24e-48a3c4d9fab7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansReceivableMember_019fd2c8-72f3-7b52-9373-6799e41901c0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LoansReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019fd2c8-72f3-7591-a482-b90d2f735ff8" xlink:to="loc_us-gaap_LoansReceivableMember_019fd2c8-72f3-7b52-9373-6799e41901c0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CurrentLiabilitiesMember_019fd2c8-72f3-7d16-90f9-4481f2e4903b" xlink:href="glxy-20260630.xsd#glxy_CurrentLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019fd2c8-72f3-7591-a482-b90d2f735ff8" xlink:to="loc_glxy_CurrentLiabilitiesMember_019fd2c8-72f3-7d16-90f9-4481f2e4903b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetsMember_019fd2c8-72f3-7280-8e6b-918c730a8dfe" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019fd2c8-72f3-7591-a482-b90d2f735ff8" xlink:to="loc_glxy_CryptoAssetsMember_019fd2c8-72f3-7280-8e6b-918c730a8dfe" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_019fd2c8-72f3-73f7-b415-86d76cc35282" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_019fd2c8-72f3-76cb-8ed0-e8933c154e0a" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_019fd2c8-72f3-73f7-b415-86d76cc35282" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_019fd2c8-72f3-73f7-b415-86d76cc35282_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_019fd2c8-72f3-73f7-b415-86d76cc35282" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_019fd2c8-72f3-73f7-b415-86d76cc35282_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_019fd2c8-72f3-7a79-80ec-5396826e06a7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_019fd2c8-72f3-73f7-b415-86d76cc35282" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_019fd2c8-72f3-7a79-80ec-5396826e06a7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_ProtocolConcentrationRiskMember_019fd2c8-72f3-7807-96c3-0ab753261b27" xlink:href="glxy-20260630.xsd#glxy_ProtocolConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_019fd2c8-72f3-7a79-80ec-5396826e06a7" xlink:to="loc_glxy_ProtocolConcentrationRiskMember_019fd2c8-72f3-7807-96c3-0ab753261b27" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_019fd2c8-72f3-75bb-a50c-9694213e602b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_019fd2c8-72f3-7a79-80ec-5396826e06a7" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_019fd2c8-72f3-75bb-a50c-9694213e602b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditConcentrationRiskMember_019fd2c8-72f3-7287-9749-f58ae1d89082" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_019fd2c8-72f3-7a79-80ec-5396826e06a7" xlink:to="loc_us-gaap_CreditConcentrationRiskMember_019fd2c8-72f3-7287-9749-f58ae1d89082" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_LiquidityConcentrationRiskMember_019fd2c8-72f3-747f-9f9e-c58ca786cca0" xlink:href="glxy-20260630.xsd#glxy_LiquidityConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_019fd2c8-72f3-7a79-80ec-5396826e06a7" xlink:to="loc_glxy_LiquidityConcentrationRiskMember_019fd2c8-72f3-747f-9f9e-c58ca786cca0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_019fd2c8-72f3-7a8e-a7b4-68b8816829f7" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_019fd2c8-72f3-76cb-8ed0-e8933c154e0a" xlink:to="loc_srt_CounterpartyNameAxis_019fd2c8-72f3-7a8e-a7b4-68b8816829f7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019fd2c8-72f3-7a8e-a7b4-68b8816829f7_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_019fd2c8-72f3-7a8e-a7b4-68b8816829f7" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019fd2c8-72f3-7a8e-a7b4-68b8816829f7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019fd2c8-72f3-73e7-9b1d-d7be45e3c901" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_019fd2c8-72f3-7a8e-a7b4-68b8816829f7" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019fd2c8-72f3-73e7-9b1d-d7be45e3c901" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_BrokersMember_019fd2c8-72f3-7755-a1bb-f07f4ed4126f" xlink:href="glxy-20260630.xsd#glxy_BrokersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019fd2c8-72f3-73e7-9b1d-d7be45e3c901" xlink:to="loc_glxy_BrokersMember_019fd2c8-72f3-7755-a1bb-f07f4ed4126f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_TradingPlatformsMember_019fd2c8-72f3-7348-bc3e-77c5df829b5d" xlink:href="glxy-20260630.xsd#glxy_TradingPlatformsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019fd2c8-72f3-73e7-9b1d-d7be45e3c901" xlink:to="loc_glxy_TradingPlatformsMember_019fd2c8-72f3-7348-bc3e-77c5df829b5d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_ThreeCounterpartiesMember_019fd2c8-72f3-72b8-9c10-e7fc4985d2ba" xlink:href="glxy-20260630.xsd#glxy_ThreeCounterpartiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019fd2c8-72f3-73e7-9b1d-d7be45e3c901" xlink:to="loc_glxy_ThreeCounterpartiesMember_019fd2c8-72f3-72b8-9c10-e7fc4985d2ba" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_OneCounterpartyMember_019fd2c8-72f3-753e-9a86-4559328ebabd" xlink:href="glxy-20260630.xsd#glxy_OneCounterpartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019fd2c8-72f3-73e7-9b1d-d7be45e3c901" xlink:to="loc_glxy_OneCounterpartyMember_019fd2c8-72f3-753e-9a86-4559328ebabd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_TwoCounterpartiesMember_019fd2c8-72f3-765e-9c0b-aeeadcfab966" xlink:href="glxy-20260630.xsd#glxy_TwoCounterpartiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019fd2c8-72f3-73e7-9b1d-d7be45e3c901" xlink:to="loc_glxy_TwoCounterpartiesMember_019fd2c8-72f3-765e-9c0b-aeeadcfab966" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_ThirdPartiesMember_019fd2c8-72f3-7347-ad40-d9292f3ed687" xlink:href="glxy-20260630.xsd#glxy_ThirdPartiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019fd2c8-72f3-73e7-9b1d-d7be45e3c901" xlink:to="loc_glxy_ThirdPartiesMember_019fd2c8-72f3-7347-ad40-d9292f3ed687" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_TwoCentralizedDigitalAssetTradingPlatformMember_019fd2c8-72f3-708d-a8be-c69646f2a8a5" xlink:href="glxy-20260630.xsd#glxy_TwoCentralizedDigitalAssetTradingPlatformMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019fd2c8-72f3-73e7-9b1d-d7be45e3c901" xlink:to="loc_glxy_TwoCentralizedDigitalAssetTradingPlatformMember_019fd2c8-72f3-708d-a8be-c69646f2a8a5" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_OneCentralizedDigitalAssetTradingPlatformMember_019fd2c8-72f3-7288-adc2-d42de4087efd" xlink:href="glxy-20260630.xsd#glxy_OneCentralizedDigitalAssetTradingPlatformMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019fd2c8-72f3-73e7-9b1d-d7be45e3c901" xlink:to="loc_glxy_OneCentralizedDigitalAssetTradingPlatformMember_019fd2c8-72f3-7288-adc2-d42de4087efd" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_019fd2c8-72f3-7bb4-9a37-4815b0807b36" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_019fd2c8-72f3-76cb-8ed0-e8933c154e0a" xlink:to="loc_srt_MajorCustomersAxis_019fd2c8-72f3-7bb4-9a37-4815b0807b36" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_019fd2c8-72f3-7bb4-9a37-4815b0807b36_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_019fd2c8-72f3-7bb4-9a37-4815b0807b36" xlink:to="loc_srt_NameOfMajorCustomerDomain_019fd2c8-72f3-7bb4-9a37-4815b0807b36_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_019fd2c8-72f3-7474-a9ea-591c6a43f3d6" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_019fd2c8-72f3-7bb4-9a37-4815b0807b36" xlink:to="loc_srt_NameOfMajorCustomerDomain_019fd2c8-72f3-7474-a9ea-591c6a43f3d6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_TwoDigitalAssetTradingPlatformsMember_019fd2c8-72f3-7b63-87e1-cb5c4c573d01" xlink:href="glxy-20260630.xsd#glxy_TwoDigitalAssetTradingPlatformsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_019fd2c8-72f3-7474-a9ea-591c6a43f3d6" xlink:to="loc_glxy_TwoDigitalAssetTradingPlatformsMember_019fd2c8-72f3-7b63-87e1-cb5c4c573d01" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_019fd2c8-72f3-7c69-8f3a-7b4bae7cecbd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_019fd2c8-72f3-78cb-962d-9a38878c930b" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_019fd2c8-72f3-7c69-8f3a-7b4bae7cecbd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019fd2c8-72f3-73cf-a7d3-f5f61c7e0508" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_019fd2c8-72f3-78cb-962d-9a38878c930b" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019fd2c8-72f3-73cf-a7d3-f5f61c7e0508" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/OPERATINGPARTNERSHIPFINANCIALINFORMATIONScheduleofConsolidatedInterimStatementsofIncomeLossDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#OPERATINGPARTNERSHIPFINANCIALINFORMATIONScheduleofConsolidatedInterimStatementsofIncomeLossDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/OPERATINGPARTNERSHIPFINANCIALINFORMATIONScheduleofConsolidatedInterimStatementsofIncomeLossDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-72f3-7a7e-9c7d-3b83f106decc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019fd2c8-72f3-7158-958c-2d0d139e13fa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-72f3-7a7e-9c7d-3b83f106decc" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019fd2c8-72f3-7158-958c-2d0d139e13fa" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_019fd2c8-72f3-71c2-a85c-a9f0db942a2e" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019fd2c8-72f3-7158-958c-2d0d139e13fa" xlink:to="loc_dei_LegalEntityAxis_019fd2c8-72f3-71c2-a85c-a9f0db942a2e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019fd2c8-72f3-71c2-a85c-a9f0db942a2e_default" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_019fd2c8-72f3-71c2-a85c-a9f0db942a2e" xlink:to="loc_dei_EntityDomain_019fd2c8-72f3-71c2-a85c-a9f0db942a2e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019fd2c8-72f3-74b0-a7c6-11cefbe27f02" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_019fd2c8-72f3-71c2-a85c-a9f0db942a2e" xlink:to="loc_dei_EntityDomain_019fd2c8-72f3-74b0-a7c6-11cefbe27f02" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_GalaxyDigitalHoldingsLPMember_019fd2c8-72f3-7f15-8ba7-75282627d513" xlink:href="glxy-20260630.xsd#glxy_GalaxyDigitalHoldingsLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_019fd2c8-72f3-74b0-a7c6-11cefbe27f02" xlink:to="loc_glxy_GalaxyDigitalHoldingsLPMember_019fd2c8-72f3-7f15-8ba7-75282627d513" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_019fd2c8-72f3-7642-88e0-103e2ad28e06" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-72f3-7a7e-9c7d-3b83f106decc" xlink:to="loc_us-gaap_Revenues_019fd2c8-72f3-7642-88e0-103e2ad28e06" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_GainsLossesFromOperations_019fd2c8-72f3-7435-b777-1cb87aca68ec" xlink:href="glxy-20260630.xsd#glxy_GainsLossesFromOperations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-72f3-7a7e-9c7d-3b83f106decc" xlink:to="loc_glxy_GainsLossesFromOperations_019fd2c8-72f3-7435-b777-1cb87aca68ec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_RevenuesAndGainsLossesFromOperations_019fd2c8-72f3-7720-9fcd-51aa000605f8" xlink:href="glxy-20260630.xsd#glxy_RevenuesAndGainsLossesFromOperations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-72f3-7a7e-9c7d-3b83f106decc" xlink:to="loc_glxy_RevenuesAndGainsLossesFromOperations_019fd2c8-72f3-7720-9fcd-51aa000605f8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpensesAbstract_019fd2c8-72f3-79a8-97ca-916cb21af2e7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingExpensesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-72f3-7a7e-9c7d-3b83f106decc" xlink:to="loc_us-gaap_OperatingExpensesAbstract_019fd2c8-72f3-79a8-97ca-916cb21af2e7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_TransactionExpenses_019fd2c8-72f3-7955-bd45-c7efc03956f0" xlink:href="glxy-20260630.xsd#glxy_TransactionExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019fd2c8-72f3-79a8-97ca-916cb21af2e7" xlink:to="loc_glxy_TransactionExpenses_019fd2c8-72f3-7955-bd45-c7efc03956f0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetImpairmentCharges_019fd2c8-72f3-7b0a-8560-9c60ad44d779" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetImpairmentCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019fd2c8-72f3-79a8-97ca-916cb21af2e7" xlink:to="loc_us-gaap_AssetImpairmentCharges_019fd2c8-72f3-7b0a-8560-9c60ad44d779" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCostAndExpenseOperating_019fd2c8-72f3-7ba8-843d-8dce7df747c9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherCostAndExpenseOperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019fd2c8-72f3-79a8-97ca-916cb21af2e7" xlink:to="loc_us-gaap_OtherCostAndExpenseOperating_019fd2c8-72f3-7ba8-843d-8dce7df747c9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenses_019fd2c8-72f3-747a-b2cd-dccf246f9267" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019fd2c8-72f3-79a8-97ca-916cb21af2e7" xlink:to="loc_us-gaap_OperatingExpenses_019fd2c8-72f3-747a-b2cd-dccf246f9267" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_019fd2c8-72f3-7981-b3e8-3ec3c87a20ef" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-72f3-7a7e-9c7d-3b83f106decc" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_019fd2c8-72f3-7981-b3e8-3ec3c87a20ef" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019fd2c8-72f3-7361-beb5-5cab7a59f171" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-72f3-7a7e-9c7d-3b83f106decc" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019fd2c8-72f3-7361-beb5-5cab7a59f171" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_019fd2c8-72f3-789f-9706-d9241ffd61d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-72f3-7a7e-9c7d-3b83f106decc" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_019fd2c8-72f3-789f-9706-d9241ffd61d8" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019fd2c8-72f3-7c75-9c2d-1293faf91acd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-72f3-7a7e-9c7d-3b83f106decc" xlink:to="loc_us-gaap_NetIncomeLoss_019fd2c8-72f3-7c75-9c2d-1293faf91acd" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019fd2c8-72f3-71ad-9d2c-f48809cdc192" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-72f3-7a7e-9c7d-3b83f106decc" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019fd2c8-72f3-71ad-9d2c-f48809cdc192" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_019fd2c8-72f3-712f-b922-b5677932c58c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ComprehensiveIncomeNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-72f3-7a7e-9c7d-3b83f106decc" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_019fd2c8-72f3-712f-b922-b5677932c58c" xlink:type="arc" order="9"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/OPERATINGPARTNERSHIPFINANCIALINFORMATIONScheduleofConsolidatedInterimStatementsofFinancialPositionDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#OPERATINGPARTNERSHIPFINANCIALINFORMATIONScheduleofConsolidatedInterimStatementsofFinancialPositionDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/OPERATINGPARTNERSHIPFINANCIALINFORMATIONScheduleofConsolidatedInterimStatementsofFinancialPositionDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-72f3-7733-ba3e-edd0d75e3735" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019fd2c8-72f3-7c8a-b501-b819ddc3b2cc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-72f3-7733-ba3e-edd0d75e3735" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019fd2c8-72f3-7c8a-b501-b819ddc3b2cc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_019fd2c8-72f3-76ba-b83a-d6b04098cada" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019fd2c8-72f3-7c8a-b501-b819ddc3b2cc" xlink:to="loc_dei_LegalEntityAxis_019fd2c8-72f3-76ba-b83a-d6b04098cada" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019fd2c8-72f3-76ba-b83a-d6b04098cada_default" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_019fd2c8-72f3-76ba-b83a-d6b04098cada" xlink:to="loc_dei_EntityDomain_019fd2c8-72f3-76ba-b83a-d6b04098cada_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019fd2c8-72f3-7d6e-95e0-a39e2f53f810" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_019fd2c8-72f3-76ba-b83a-d6b04098cada" xlink:to="loc_dei_EntityDomain_019fd2c8-72f3-7d6e-95e0-a39e2f53f810" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_GalaxyDigitalHoldingsLPMember_019fd2c8-72f3-7265-ae66-3b2250b2a31b" xlink:href="glxy-20260630.xsd#glxy_GalaxyDigitalHoldingsLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_019fd2c8-72f3-7d6e-95e0-a39e2f53f810" xlink:to="loc_glxy_GalaxyDigitalHoldingsLPMember_019fd2c8-72f3-7265-ae66-3b2250b2a31b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_019fd2c8-72f3-7aa4-a8ec-c8c119c53850" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-72f3-7733-ba3e-edd0d75e3735" xlink:to="loc_us-gaap_AssetsAbstract_019fd2c8-72f3-7aa4-a8ec-c8c119c53850" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019fd2c8-72f3-7855-89ad-a51fbd19a7be" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019fd2c8-72f3-7aa4-a8ec-c8c119c53850" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019fd2c8-72f3-7855-89ad-a51fbd19a7be" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetIntangibleAssetsCurrent_019fd2c8-72f3-78a6-995a-62b72d2672a5" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetIntangibleAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019fd2c8-72f3-7aa4-a8ec-c8c119c53850" xlink:to="loc_glxy_CryptoAssetIntangibleAssetsCurrent_019fd2c8-72f3-78a6-995a-62b72d2672a5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetReceivableRestrictedCurrent_019fd2c8-72f3-70bc-9a9c-0582f4a2e795" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetReceivableRestrictedCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019fd2c8-72f3-7aa4-a8ec-c8c119c53850" xlink:to="loc_glxy_CryptoAssetReceivableRestrictedCurrent_019fd2c8-72f3-70bc-9a9c-0582f4a2e795" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesAndLoansReceivableNetCurrent_019fd2c8-72f3-783a-bbb3-7021695b31b6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesAndLoansReceivableNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019fd2c8-72f3-7aa4-a8ec-c8c119c53850" xlink:to="loc_us-gaap_NotesAndLoansReceivableNetCurrent_019fd2c8-72f3-783a-bbb3-7021695b31b6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermInvestments_019fd2c8-72f3-7a46-82ce-d14f7c169711" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019fd2c8-72f3-7aa4-a8ec-c8c119c53850" xlink:to="loc_us-gaap_LongTermInvestments_019fd2c8-72f3-7a46-82ce-d14f7c169711" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_AssetsPostedAsCollateralCurrent_019fd2c8-72f3-7f5f-9d63-1ee2e1c8013f" xlink:href="glxy-20260630.xsd#glxy_AssetsPostedAsCollateralCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019fd2c8-72f3-7aa4-a8ec-c8c119c53850" xlink:to="loc_glxy_AssetsPostedAsCollateralCurrent_019fd2c8-72f3-7f5f-9d63-1ee2e1c8013f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLossCurrent_019fd2c8-72f3-777c-8921-859728728a25" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLossCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019fd2c8-72f3-7aa4-a8ec-c8c119c53850" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLossCurrent_019fd2c8-72f3-777c-8921-859728728a25" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_019fd2c8-72f3-7083-a212-6fbc86c7b90b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019fd2c8-72f3-7aa4-a8ec-c8c119c53850" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_019fd2c8-72f3-7083-a212-6fbc86c7b90b" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_019fd2c8-72f3-7772-becf-39f7916b40b2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019fd2c8-72f3-7aa4-a8ec-c8c119c53850" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_019fd2c8-72f3-7772-becf-39f7916b40b2" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_019fd2c8-72f3-7e02-b653-ca6316a8c438" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019fd2c8-72f3-7aa4-a8ec-c8c119c53850" xlink:to="loc_us-gaap_Assets_019fd2c8-72f3-7e02-b653-ca6316a8c438" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019fd2c8-72f3-727c-997e-91da1d1c89ae" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019fd2c8-72f3-7733-ba3e-edd0d75e3735" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019fd2c8-72f3-727c-997e-91da1d1c89ae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CryptoAssetPayableNoncurrent_019fd2c8-72f3-7a4a-9921-b50d5786a09c" xlink:href="glxy-20260630.xsd#glxy_CryptoAssetPayableNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019fd2c8-72f3-727c-997e-91da1d1c89ae" xlink:to="loc_glxy_CryptoAssetPayableNoncurrent_019fd2c8-72f3-7a4a-9921-b50d5786a09c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansPayableCurrent_019fd2c8-72f3-723f-bb42-05882401f7cf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LoansPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019fd2c8-72f3-727c-997e-91da1d1c89ae" xlink:to="loc_us-gaap_LoansPayableCurrent_019fd2c8-72f3-723f-bb42-05882401f7cf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_CollateralPayableCurrent_019fd2c8-72f3-7d0d-ac2d-14e1b0997c15" xlink:href="glxy-20260630.xsd#glxy_CollateralPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019fd2c8-72f3-727c-997e-91da1d1c89ae" xlink:to="loc_glxy_CollateralPayableCurrent_019fd2c8-72f3-7d0d-ac2d-14e1b0997c15" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermNotesPayable_019fd2c8-72f3-785c-9aee-7942ae09af5a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermNotesPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019fd2c8-72f3-727c-997e-91da1d1c89ae" xlink:to="loc_us-gaap_LongTermNotesPayable_019fd2c8-72f3-785c-9aee-7942ae09af5a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_019fd2c8-72f3-7bf6-814d-1d26c219ba2d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019fd2c8-72f3-727c-997e-91da1d1c89ae" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_019fd2c8-72f3-7bf6-814d-1d26c219ba2d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_019fd2c8-72f3-782d-b555-29409d052b4f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Liabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019fd2c8-72f3-727c-997e-91da1d1c89ae" xlink:to="loc_us-gaap_Liabilities_019fd2c8-72f3-782d-b555-29409d052b4f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapital_019fd2c8-72f3-7632-8948-8f8dc599da07" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PartnersCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019fd2c8-72f3-727c-997e-91da1d1c89ae" xlink:to="loc_us-gaap_PartnersCapital_019fd2c8-72f3-7632-8948-8f8dc599da07" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_019fd2c8-72f3-7666-afae-fc66dc7b8835" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019fd2c8-72f3-727c-997e-91da1d1c89ae" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_019fd2c8-72f3-7666-afae-fc66dc7b8835" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.galaxy.com/role/SUBSEQUENTEVENTSDetails" xlink:type="simple" xlink:href="glxy-20260630.xsd#SUBSEQUENTEVENTSDetails"/>
  <link:definitionLink xlink:role="http://www.galaxy.com/role/SUBSEQUENTEVENTSDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventLineItems_019fd2c8-72f3-723a-a5e6-de79e6bc3a1e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTable_019fd2c8-72f3-71ef-bdda-f58e43977916" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_019fd2c8-72f3-723a-a5e6-de79e6bc3a1e" xlink:to="loc_us-gaap_SubsequentEventTable_019fd2c8-72f3-71ef-bdda-f58e43977916" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_019fd2c8-72f3-7caf-90fd-91acb97c6fc0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_019fd2c8-72f3-71ef-bdda-f58e43977916" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_019fd2c8-72f3-7caf-90fd-91acb97c6fc0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019fd2c8-72f3-7caf-90fd-91acb97c6fc0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019fd2c8-72f3-7caf-90fd-91acb97c6fc0" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019fd2c8-72f3-7caf-90fd-91acb97c6fc0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019fd2c8-72f3-7c59-919b-711f3234836f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019fd2c8-72f3-7caf-90fd-91acb97c6fc0" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019fd2c8-72f3-7c59-919b-711f3234836f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_019fd2c8-72f3-7770-a159-71f3c1e7025c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_019fd2c8-72f3-7c59-919b-711f3234836f" xlink:to="loc_us-gaap_SubsequentEventMember_019fd2c8-72f3-7770-a159-71f3c1e7025c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019fd2c8-72f3-74c0-97b7-144e617317e6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_019fd2c8-72f3-71ef-bdda-f58e43977916" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019fd2c8-72f3-74c0-97b7-144e617317e6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019fd2c8-72f3-74c0-97b7-144e617317e6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019fd2c8-72f3-74c0-97b7-144e617317e6" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019fd2c8-72f3-74c0-97b7-144e617317e6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019fd2c8-72f3-7c82-a965-f2fd2fea30bb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019fd2c8-72f3-74c0-97b7-144e617317e6" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019fd2c8-72f3-7c82-a965-f2fd2fea30bb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_019fd2c8-72f3-702b-8211-beed3e58d1e3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019fd2c8-72f3-7c82-a965-f2fd2fea30bb" xlink:to="loc_us-gaap_SecuredDebtMember_019fd2c8-72f3-702b-8211-beed3e58d1e3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019fd2c8-72f3-748d-ae68-94eeee7c0a35" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_019fd2c8-72f3-71ef-bdda-f58e43977916" xlink:to="loc_us-gaap_DebtInstrumentAxis_019fd2c8-72f3-748d-ae68-94eeee7c0a35" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019fd2c8-72f3-748d-ae68-94eeee7c0a35_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019fd2c8-72f3-748d-ae68-94eeee7c0a35" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019fd2c8-72f3-748d-ae68-94eeee7c0a35_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019fd2c8-72f3-7fc0-9ee0-fa2777d39a3e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019fd2c8-72f3-748d-ae68-94eeee7c0a35" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019fd2c8-72f3-7fc0-9ee0-fa2777d39a3e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_SeniorNotesDue2031Member_019fd2c8-72f3-79e5-9596-d8b2e5e3dee7" xlink:href="glxy-20260630.xsd#glxy_SeniorNotesDue2031Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019fd2c8-72f3-7fc0-9ee0-fa2777d39a3e" xlink:to="loc_glxy_SeniorNotesDue2031Member_019fd2c8-72f3-79e5-9596-d8b2e5e3dee7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019fd9f3-5824-77dc-b274-9feac146c45d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_019fd2c8-72f3-71ef-bdda-f58e43977916" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019fd9f3-5824-77dc-b274-9feac146c45d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019fd9f3-5824-77dc-b274-9feac146c45d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019fd9f3-5824-77dc-b274-9feac146c45d" xlink:to="loc_us-gaap_ClassOfStockDomain_019fd9f3-5824-77dc-b274-9feac146c45d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019fd9f3-5824-7c10-bb9e-423364f2f834" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019fd9f3-5824-77dc-b274-9feac146c45d" xlink:to="loc_us-gaap_ClassOfStockDomain_019fd9f3-5824-7c10-bb9e-423364f2f834" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_019fd9f3-5824-79c1-9e14-41579c94b47e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019fd9f3-5824-7c10-bb9e-423364f2f834" xlink:to="loc_us-gaap_CommonClassAMember_019fd9f3-5824-79c1-9e14-41579c94b47e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_019fd2c8-72f3-7eb4-8370-2c49a33e2bc4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019fd2c8-72f3-723a-a5e6-de79e6bc3a1e" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_019fd2c8-72f3-7eb4-8370-2c49a33e2bc4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019fd2c8-72f3-702f-b1ff-0fb35c0dc55f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019fd2c8-72f3-723a-a5e6-de79e6bc3a1e" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019fd2c8-72f3-702f-b1ff-0fb35c0dc55f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodShares_019fdc7c-6f77-7fa8-a136-c7429a6e41fd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockRepurchasedDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019fd2c8-72f3-723a-a5e6-de79e6bc3a1e" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodShares_019fdc7c-6f77-7fa8-a136-c7429a6e41fd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodValue_019fd9f3-5824-7c32-8cce-65d5d433203b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockRepurchasedDuringPeriodValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019fd2c8-72f3-723a-a5e6-de79e6bc3a1e" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodValue_019fd9f3-5824-7c32-8cce-65d5d433203b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_019fed2e-b3f9-7079-ba5e-62e9c36c58f2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019fd2c8-72f3-723a-a5e6-de79e6bc3a1e" xlink:to="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_019fed2e-b3f9-7079-ba5e-62e9c36c58f2" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://xbrl.sec.gov/ecd/role/IndividualsOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd#IndividualsOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/ecd/role/IndividualsOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AllIndividualsMember" xlink:href="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd#ecd_AllIndividualsMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_ErinBrownMember_019fd2c8-6d32-7a3b-90cb-8a34336b4bf3" xlink:href="glxy-20260630.xsd#glxy_ErinBrownMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_glxy_ErinBrownMember_019fd2c8-6d32-7a3b-90cb-8a34336b4bf3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_glxy_MatthewFriedrichMember_019fd2c8-6d32-7fab-af3e-73a327f4c2e4" xlink:href="glxy-20260630.xsd#glxy_MatthewFriedrichMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_glxy_MatthewFriedrichMember_019fd2c8-6d32-7fab-af3e-73a327f4c2e4" xlink:type="arc" order="3"/>
  </link:definitionLink>
</link:linkbase>
