This study explores the language habitus and practices in one Vietnamese immigrant family in Melbourne. It contributes to research on family language policy in multicultural contexts. Using a Bourdieusian framework to explore the interrelationships between language beliefs, practices and management in a nuanced way, the article discusses how the children's and adults' language beliefs are situated in their lived experiences as a result of their participation in the different social fields of family, school, and the workplace. The article then further examines the "structuring" feature of the habitus through an exploration of the children's agency in family language policy in two aspects: their manifestation of their agency as well as how their habitus and their accumulated capital shape their language practices. Findings point to the shared multilingual habitus between the grandmother, mother and the two children and children's agency in family language practices and management. The data analysis and theoretical discussions suggest that Bourdieu's concepts are useful and nuanced lenses to investigate family language policy and are complementary to Spolsky's seminal theoretical framework of family language policy.