Language is commonly understood as a primary resource for enacting social identity and displaying membership of social groups. In this article I explore the links between second-language use, membership, and social contexts through the accounts of recently arrived immigrant students in Australian high schools. I argue that a key notion linking language use and identity is that of self-representation. The ways in which these students represent themselves, and are represented in schools, are critically related to the types of social interactions they participate in and to their ongoing language acquisition and integration into mainstream school and other social contexts. I contend that for schools to attend more effectively to the identities and self-representations of students from non-English-speaking backgrounds, they must first understand the dynamic interrelations of institutional contexts, language resources, and social identities.