<?xml version="1.0" encoding="US-ASCII"?>
<!--XBRL Document Created with Wdesk from Workiva-->
<!-- -->
<link:linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <link:roleRef roleURI="http://www.lgi.com/role/DocumentAndEntityInformation" xlink:href="lbtya-20200803.xsd#DocumentAndEntityInformation" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" xlink:type="simple" />
  <link:definitionLink xlink:role="http://www.lgi.com/role/DocumentAndEntityInformation" xlink:type="extended">
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityInformationLineItems" xlink:label="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:type="locator" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntitiesTable" xlink:label="loc_dei_EntitiesTable_7DF12250EE0B50BAFB78AB03A7EE43B7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_EntitiesTable_7DF12250EE0B50BAFB78AB03A7EE43B7" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_F8450828A9DE3BCD0E5DAB03A7EE5C13" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_7DF12250EE0B50BAFB78AB03A7EE43B7" xlink:to="loc_us-gaap_StatementClassOfStockAxis_F8450828A9DE3BCD0E5DAB03A7EE5C13" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_EE68284165218AC657A0AB03A7EEF3B8_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_F8450828A9DE3BCD0E5DAB03A7EE5C13" xlink:to="loc_us-gaap_ClassOfStockDomain_EE68284165218AC657A0AB03A7EEF3B8_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_EE68284165218AC657A0AB03A7EEF3B8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_F8450828A9DE3BCD0E5DAB03A7EE5C13" xlink:to="loc_us-gaap_ClassOfStockDomain_EE68284165218AC657A0AB03A7EEF3B8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonClassAMember" xlink:label="loc_us-gaap_CommonClassAMember_C309AD0914E033F9B1C8AB03A7EF3F09" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_EE68284165218AC657A0AB03A7EEF3B8" xlink:to="loc_us-gaap_CommonClassAMember_C309AD0914E033F9B1C8AB03A7EF3F09" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonClassBMember" xlink:label="loc_us-gaap_CommonClassBMember_4E566B8A99465D003F17AB03A7EFC2DD" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_EE68284165218AC657A0AB03A7EEF3B8" xlink:to="loc_us-gaap_CommonClassBMember_4E566B8A99465D003F17AB03A7EFC2DD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonClassCMember" xlink:label="loc_us-gaap_CommonClassCMember_998F06ED0528E95422E9AB03A7EFF21B" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_EE68284165218AC657A0AB03A7EEF3B8" xlink:to="loc_us-gaap_CommonClassCMember_998F06ED0528E95422E9AB03A7EFF21B" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentType" xlink:label="loc_dei_DocumentType_22DD1ECEE477D101E9BDAB03A7F0374B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_DocumentType_22DD1ECEE477D101E9BDAB03A7F0374B" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentPeriodEndDate" xlink:label="loc_dei_DocumentPeriodEndDate_765D316C8ACF490E9B87AB03A7F0D70A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_DocumentPeriodEndDate_765D316C8ACF490E9B87AB03A7F0D70A" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityRegistrantName" xlink:label="loc_dei_EntityRegistrantName_DF9F045CD7670D6DC911AB03A7F17C81" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_EntityRegistrantName_DF9F045CD7670D6DC911AB03A7F17C81" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityCentralIndexKey" xlink:label="loc_dei_EntityCentralIndexKey_A062A7861A115A46F721AB03A7F1ABE7" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_EntityCentralIndexKey_A062A7861A115A46F721AB03A7F1ABE7" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_AmendmentFlag" xlink:label="loc_dei_AmendmentFlag_2D7A6B4CBD86490C4B28AB03A7F1633B" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_AmendmentFlag_2D7A6B4CBD86490C4B28AB03A7F1633B" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityIncorporationStateCountryCode" xlink:label="loc_dei_EntityIncorporationStateCountryCode_1A2CC32E216703D375F1AB03A7F13972" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_EntityIncorporationStateCountryCode_1A2CC32E216703D375F1AB03A7F13972" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityFileNumber" xlink:label="loc_dei_EntityFileNumber_9D873DAE8DD159740E2EAB03A7F11441" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_EntityFileNumber_9D873DAE8DD159740E2EAB03A7F11441" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityTaxIdentificationNumber" xlink:label="loc_dei_EntityTaxIdentificationNumber_2CB5B886A067828302BFAB03A7F18C18" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_EntityTaxIdentificationNumber_2CB5B886A067828302BFAB03A7F18C18" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityAddressAddressLine1" xlink:label="loc_dei_EntityAddressAddressLine1_A0301B31DE871F71F1E3AB03A7F29239" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_EntityAddressAddressLine1_A0301B31DE871F71F1E3AB03A7F29239" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityAddressAddressLine2" xlink:label="loc_dei_EntityAddressAddressLine2_D56EDF004E82A7978399AB03A7F28296" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_EntityAddressAddressLine2_D56EDF004E82A7978399AB03A7F28296" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityAddressCityOrTown" xlink:label="loc_dei_EntityAddressCityOrTown_A47D44FC58B5E9EE6800AB03A7F21168" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_EntityAddressCityOrTown_A47D44FC58B5E9EE6800AB03A7F21168" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityAddressCountry" xlink:label="loc_dei_EntityAddressCountry_5326B6B429B6E4B75B39AB03A7F28F46" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_EntityAddressCountry_5326B6B429B6E4B75B39AB03A7F28F46" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityAddressPostalZipCode" xlink:label="loc_dei_EntityAddressPostalZipCode_D420FAF299EDD845835EAB03A7F3809E" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_EntityAddressPostalZipCode_D420FAF299EDD845835EAB03A7F3809E" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_CountryRegion" xlink:label="loc_dei_CountryRegion_F0DBCACA5ADA12DA2D30AB03A7F3BC19" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_CountryRegion_F0DBCACA5ADA12DA2D30AB03A7F3BC19" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_CityAreaCode" xlink:label="loc_dei_CityAreaCode_AE8DC258B2B6BD0065E5AB03A7F3E87F" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_CityAreaCode_AE8DC258B2B6BD0065E5AB03A7F3E87F" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_LocalPhoneNumber" xlink:label="loc_dei_LocalPhoneNumber_33D40FC74B705E75A486AB03A7F35A03" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_LocalPhoneNumber_33D40FC74B705E75A486AB03A7F35A03" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_Security12bTitle" xlink:label="loc_dei_Security12bTitle_BF3D5069C0E7A3E90F1DAB03A7F3DB8D" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_Security12bTitle_BF3D5069C0E7A3E90F1DAB03A7F3DB8D" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_TradingSymbol" xlink:label="loc_dei_TradingSymbol_01ABE22E449FF499874CAB03A7F37BD9" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_TradingSymbol_01ABE22E449FF499874CAB03A7F37BD9" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_SecurityExchangeName" xlink:label="loc_dei_SecurityExchangeName_3000C7A201CCF27A181FAB03A7F41E00" xlink:type="locator" />
    <link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_SecurityExchangeName_3000C7A201CCF27A181FAB03A7F41E00" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_WrittenCommunications" xlink:label="loc_dei_WrittenCommunications_45253B0D2A5AD076FEE5AB03A7F40375" xlink:type="locator" />
    <link:definitionArc order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_WrittenCommunications_45253B0D2A5AD076FEE5AB03A7F40375" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_SolicitingMaterial" xlink:label="loc_dei_SolicitingMaterial_C9C1FE82735424539CF0AB03A7F4BF70" xlink:type="locator" />
    <link:definitionArc order="21" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_SolicitingMaterial_C9C1FE82735424539CF0AB03A7F4BF70" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_PreCommencementTenderOffer" xlink:label="loc_dei_PreCommencementTenderOffer_8E07E48E55BB96680B8EAB03A7F4C281" xlink:type="locator" />
    <link:definitionArc order="22" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_PreCommencementTenderOffer_8E07E48E55BB96680B8EAB03A7F4C281" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_PreCommencementIssuerTenderOffer" xlink:label="loc_dei_PreCommencementIssuerTenderOffer_43DCDEF7B4BE4DA90884AB03A7F4BDF5" xlink:type="locator" />
    <link:definitionArc order="23" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_PreCommencementIssuerTenderOffer_43DCDEF7B4BE4DA90884AB03A7F4BDF5" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityEmergingGrowthCompany" xlink:label="loc_dei_EntityEmergingGrowthCompany_D231C15AE8B6A3434A22AB03A7F5EA7D" xlink:type="locator" />
    <link:definitionArc order="24" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_734BE3B2A177EAFB03F4AB03A7F04EAF" xlink:to="loc_dei_EntityEmergingGrowthCompany_D231C15AE8B6A3434A22AB03A7F5EA7D" xlink:type="arc" />
  </link:definitionLink>
</link:linkbase>
