Although numerous studies have examined racial/ethnic inequalities in collegiate student outcomes, serious attention to disparities in post-secondary student learning has emerged only recently. Using a national sample of 35,000 college seniors and 250 diverse institutions from the Collegiate Learning Assessment, this study investigates the role of institutional characteristics in promoting the development of higher-order cognitive skills and the equitable distribution of these skills by student racial/ethnic background. Using three-level hierarchical linear models within an analysis of covariance framework, we find that the initial academic gaps that separate African American students from their white peers widen even further during college. Although substantial academic disparities exist between Hispanic and white students at both college entry and exit, Hispanic and white students gain academic skills at statistically comparable rates. Importantly, racial/ethnic differences in cognitive development vary across institutions partly as a function of institutional characteristics. In particular, even after accounting for a host of student- and institution-level characteristics, African American/white and Hispanic/white inequalities are somewhat smaller at colleges that enroll larger proportions of non-white students. However, these benefits of increased minority enrollments are contingent upon the academic backgrounds of students' peers, with academically weaker student enrollments in some cases negating the benefits of increased racial/ethnic diversity.