This study examines the mathematics course-taking of White, African American, and Latino students in racially diverse schools and the effects of different opportunity structures in those schools on college preparation and college-going. This study uses data from the Adolescent Health and Academic Achievement Study (AHAA) and its partner study, the National Longitudinal Study of Adolescent Health (Add Health). Evidence consistently suggests that schools can play an active role in the provision of opportunities for social mobility or in the exacerbation of social inequality, depending on how they are structured.