The peer group is an important developmental context for children. In this paper we present a method to operationalize a child's integration into the classroom by their informal social classroom roles, which we obtained using a blockmodel analysis based on role equivalence. This method differs in several respects from the common socio-metric status approach. Analysis of multiplex social relationships of 1,241 first-grade children in 71 classrooms showed nine empirical classroom roles. The roles were not associated with physical attractiveness not with ethnic ancestry, were associated only weakly with age, sex, and intelligence, and were associated strongly with school adjustment. Classroom roles and sociometric status were clearly associated, but measured different aspects of a child's integration into the classroom. For all school problems except academic performance, classroom roles explained a much larger proportion of the variance than did sociometric status. (Contains 2 figures and 5 tables.)