Governmental language policies in China have varied across recent decades, including the intensive promotion of Mandarin as a language of unification and public championing of regional varieties. Concomitantly, increasing urbanisation, regional migration, and cross-linguistic marriage have led to greater use of Mandarin in private domains. Given the varied status of regional language varieties by city, language ideologies and home practices play an increasingly important role in shaping youth language proficiencies, and maintaining dialect diversity. This paper examines links between parental language ideologies and child language proficiencies in three Chinese cities. The analysis of 167 interviews with young adult children and their parents reveals that parents tend to hold one of four ideological stances: Mandarin-dominant, dialect-dominant, bilingual diglossic, and 'whatever works'. Furthermore, we find that location matters: families differ by region in their ideologies and support for local varieties. Moreover, parental language ideology predicted children's current language proficiencies: parents who reported having explicit pro-Mandarin language ideology tended to have young adult children with lower levels of reported skill in the regional dialect. However, the strength of that relationship varies by city. We conclude by considering the implications of these findings for language policy and the promotion of dialect diversity.