Hija miżżewġa lill-attur Svante Thunberg u flimkien għandhom żewġt itfal bniet: il-kantanta Beata Ernman<ref>{{Ċita web|titlu=Greta Thunberg's sister launches her singing career {{!}} DW {{!}} 18.02.2020|url=https://www.dw.com/en/greta-thunbergs-sister-launches-her-singing-career/a-52419740 |kunjom1=Mund |isem1=DeutscheHeike |kunjom1data=Welle18 Frar 2020 (www.dw.com)|data-aċċess=9 Marzu 2021-03-09|lingwa=en-GB|sit=DW.COM}}</ref> u l-attivitsta ambjentali [[Greta Thunberg]].<ref>{{Ċita web|titlu=Greta Thunberg’s mother is actually an incredible opera singer|url=https://www.classicfm.com/music-news/greta-thunberg-mother-opera-singer-malena-ernman/|data-aċċess=2021-03-09|lingwa=en|sit=Classic FM}}</ref>
