While research on education and conflict has explored how schooling exacerbates or facilitates intergroup relations, fewer studies have examined the role of interpersonal relationships in schools in mitigating larger societal conflicts. This research explores friendship patterns within diverse schools through the case of Federal Unity Colleges (FUCs) in Nigeria, a diverse nation with prominent group categorizations that overlap across ethnic, religious, regional, and socioeconomic lines. This mixed-methods longitudinal research was based on extensive fieldwork in eight secondary schools (six FUCs, two state) over one academic year in Nigeria (2017-18). Through an analysis of social networks, I find that FUC students tend to divide close friendships by religion while state school students divide by ethnicity. Varying school practices shaping this outcome are explored using interview data. The findings contribute to literature and theory related to education in conflict, diverse schools, and school relationship to the nation.