Research on school desegregation in South Africa has largely documented an assimilationist process. As in educational contexts elsewhere, the assimilationist position presupposes that learners from non-dominant groups are made to change their ways of being on entering schools from which they were previously excluded. Drawing on an ethnographic case-study of a suburban girls' school in Johannesburg, South Africa, where "black" learners have replaced "white" learners, as well as on post-structuralist theorizing of "discourse" and "identity", this paper engages with and critiques the assimilationist position. I reconstruct the discursive positioning of the girls within official school discourses, thus highlighting the powerful assimilationist project of the school, but go on to explore the ways in which the learners use a range of semiotic resources not valued in official school discourses to subvert their positioning. I conclude that in inhabiting the school, the girls experience both repressive and liberatory effects, and they themselves produce mobile points of resistance. (Contains 5 notes.)