This study seeks to understand the role of family language policy (FLP) in the process of language shift from Bantu languages into Portuguese, the powerful and prestigious language in Mozambique. The study is based on thematic analysis of semi-structured focus group interviews with urban middle class parents of young citizens born after the independence of the country in 1975. Drawing on a critical, multi-layered approach that recognises the national, institutional and interpersonal layers of language policy work, where FLP is located, this study contributes to question Fishman's (Reversing language shift: Theoretical and empirical foundations of assistance to threatened languages, Multiling Matters, 1991; in: Bathia TK, Ritchie WR (eds) The handbook of bilingualism, Blackwell, 2006) view of family and intergenerational transmission as central for language maintenance, and to move beyond Spolsky's (Language policy, Cambridge University Press, 2004; J Multiling Multicult Dev 33:3-11, 2012) tripartite model of language policy. We found that, pressured by a combination of instrumental, sociodemographic and politico-ideological forces, urban middle class parents choose to invest in the transmission of Portuguese to their children at the expense of Bantu languages, which is often in conflict with their sociocultural desires, particularly the desire to preserve their native languages and cultures, and to ensure intergenerational ties. We argue that this preference for the Portuguese language is contributing to pave the way for language shift in Mozambique. This is the first study to explore the drivers of language shift in the family context in Mozambique, contributing, among others, to understand the dilemmas and challenges faced by families in the management of bi/multilingualism in diglossic postcolonial contexts.