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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:01a18428-a4eb-7237-a5ce-0d5166c8097b,g:5daa6033-ae4c-4961-81c0-3d03eff85a24-->
<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://libertyglobal.com/role/DocumentandEntityInformation" xlink:type="simple" xlink:href="lbtya-20261028.xsd#DocumentandEntityInformation"/>
  <link:definitionLink xlink:role="http://libertyglobal.com/role/DocumentandEntityInformation" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInformationLineItems_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitiesTable_01a18428-a4eb-79cc-8ff2-7de08fa6fdee" 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_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_EntitiesTable_01a18428-a4eb-79cc-8ff2-7de08fa6fdee" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_01a18428-a4eb-7c75-a03c-d739ab48a620" 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_01a18428-a4eb-79cc-8ff2-7de08fa6fdee" xlink:to="loc_us-gaap_StatementClassOfStockAxis_01a18428-a4eb-7c75-a03c-d739ab48a620" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_01a18428-a4eb-7c75-a03c-d739ab48a620_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_01a18428-a4eb-7c75-a03c-d739ab48a620" xlink:to="loc_us-gaap_ClassOfStockDomain_01a18428-a4eb-7c75-a03c-d739ab48a620_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_01a18428-a4eb-7f0e-af1e-ac316bef8306" 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_01a18428-a4eb-7c75-a03c-d739ab48a620" xlink:to="loc_us-gaap_ClassOfStockDomain_01a18428-a4eb-7f0e-af1e-ac316bef8306" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_01a18428-a4eb-7969-9617-e77f3909dcc4" 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_01a18428-a4eb-7f0e-af1e-ac316bef8306" xlink:to="loc_us-gaap_CommonClassAMember_01a18428-a4eb-7969-9617-e77f3909dcc4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassBMember_01a18428-a4eb-70b7-ae6b-0247f9345766" 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_01a18428-a4eb-7f0e-af1e-ac316bef8306" xlink:to="loc_us-gaap_CommonClassBMember_01a18428-a4eb-70b7-ae6b-0247f9345766" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassCMember_01a18428-a4eb-748f-9c65-8b1628c8fe9d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonClassCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_01a18428-a4eb-7f0e-af1e-ac316bef8306" xlink:to="loc_us-gaap_CommonClassCMember_01a18428-a4eb-748f-9c65-8b1628c8fe9d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_01a18428-a4eb-76cf-b6ab-d690e9d4f724" 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_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_EntityCentralIndexKey_01a18428-a4eb-76cf-b6ab-d690e9d4f724" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_01a18428-a4eb-726f-8dc1-2ee6c4a48683" 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_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_AmendmentFlag_01a18428-a4eb-726f-8dc1-2ee6c4a48683" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate_01a18428-a4eb-75e1-bc35-145b967aee15" 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_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_CurrentFiscalYearEndDate_01a18428-a4eb-75e1-bc35-145b967aee15" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_01a18428-a4eb-7b14-9dec-9dd3f7739e0c" 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_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_DocumentType_01a18428-a4eb-7b14-9dec-9dd3f7739e0c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_01a18428-a4eb-71ae-8cbb-fc8156c079d8" 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_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_DocumentPeriodEndDate_01a18428-a4eb-71ae-8cbb-fc8156c079d8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_01a18428-a4eb-7195-9f8d-d4e1139b88f6" 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_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_EntityRegistrantName_01a18428-a4eb-7195-9f8d-d4e1139b88f6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_01a18428-a4eb-73be-9ea3-d679de351a26" 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_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_EntityIncorporationStateCountryCode_01a18428-a4eb-73be-9ea3-d679de351a26" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_01a18428-a4eb-7399-a5c8-50ca94d8c48d" 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_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_EntityFileNumber_01a18428-a4eb-7399-a5c8-50ca94d8c48d" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_01a18428-a4eb-7437-9ac8-58ea9face092" 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_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_EntityTaxIdentificationNumber_01a18428-a4eb-7437-9ac8-58ea9face092" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_01a18428-a4eb-7eae-a63d-3c008f3fb541" 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_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_EntityAddressAddressLine1_01a18428-a4eb-7eae-a63d-3c008f3fb541" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine2_01a18428-a4eb-735b-b80a-47f94e0e5bd2" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressAddressLine2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_EntityAddressAddressLine2_01a18428-a4eb-735b-b80a-47f94e0e5bd2" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_01a18428-a4eb-7a01-b06b-2e62405174ee" 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_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_EntityAddressCityOrTown_01a18428-a4eb-7a01-b06b-2e62405174ee" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCountry_01a18428-a4eb-77fa-9908-9b6ca3000dd4" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressCountry"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_EntityAddressCountry_01a18428-a4eb-77fa-9908-9b6ca3000dd4" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_01a18428-a4eb-720d-af83-d3f430c84a62" 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_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_EntityAddressPostalZipCode_01a18428-a4eb-720d-af83-d3f430c84a62" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CountryRegion_01a18428-a4eb-78ce-bb51-dbf73d350346" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CountryRegion"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_CountryRegion_01a18428-a4eb-78ce-bb51-dbf73d350346" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_01a18428-a4eb-7d05-bacf-9c467ab9b080" 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_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_CityAreaCode_01a18428-a4eb-7d05-bacf-9c467ab9b080" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_01a18428-a4eb-7019-928f-c9736bc95f37" 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_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_LocalPhoneNumber_01a18428-a4eb-7019-928f-c9736bc95f37" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_01a18428-a4eb-7eaf-9974-a3e668f2bb41" 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_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_Security12bTitle_01a18428-a4eb-7eaf-9974-a3e668f2bb41" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_01a18428-a4eb-7a91-82e4-cd443e3da9f8" 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_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_TradingSymbol_01a18428-a4eb-7a91-82e4-cd443e3da9f8" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_01a18428-a4eb-75ae-8367-3b10745f5a98" 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_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_SecurityExchangeName_01a18428-a4eb-75ae-8367-3b10745f5a98" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_WrittenCommunications_01a18428-a4eb-70c6-9648-5373ccff20f8" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_WrittenCommunications"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_WrittenCommunications_01a18428-a4eb-70c6-9648-5373ccff20f8" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SolicitingMaterial_01a18428-a4eb-7fde-8861-7207b6dc7773" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SolicitingMaterial"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_SolicitingMaterial_01a18428-a4eb-7fde-8861-7207b6dc7773" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementTenderOffer_01a18428-a4eb-7d53-be11-167c7f0a006b" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_PreCommencementTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_PreCommencementTenderOffer_01a18428-a4eb-7d53-be11-167c7f0a006b" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementIssuerTenderOffer_01a18428-a4eb-7dc1-9bae-d1125adc9762" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_PreCommencementIssuerTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_PreCommencementIssuerTenderOffer_01a18428-a4eb-7dc1-9bae-d1125adc9762" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_01a18428-a4eb-795a-884a-bba63ca4301f" 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_01a18428-a4eb-700a-83b7-a11edee964cb" xlink:to="loc_dei_EntityEmergingGrowthCompany_01a18428-a4eb-795a-884a-bba63ca4301f" xlink:type="arc" order="24"/>
  </link:definitionLink>
</link:linkbase>
