In this article, the authors use social network analysis and multilevel modeling to examine a central feature of classroom social organization: the ethnic composition of the classroom. They examine classroom ethnic composition as it relates to patterns of social integration between African American and European American children. They asked whether the social integration patterns of black and white students vary according to whether their classroom has a clear ethnic majority and, if so, whether the numerically preponderant group is African American or European American. They hypothesized that integration patterns within majority black and majority white classrooms would depend on children's status as a numerical majority or minority in the classroom and also on minority status in the macrosystemic culture. As such, a white student in a majority black classroom should have different integration patterns from a black student in a majority white classroom. (Contains 4 tables and 5 figures.)