In light of rapid demographic shifts and legal challenges to affirmative action in the United States, the issue of diversity on college campuses is of increasing importance. Most syntheses of research on diversity interactions and educational outcomes have focused on attitude change, such as reductions in prejudice or racial bias. Despite the presence of numerous studies on college diversity experiences and cognitive development, no research has systematically reviewed the literature on this topic. The current study uses meta-analysis to examine this relationship systematically. The findings suggest that several types of diversity experiences are positively related to several cognitive outcomes, but the magnitude of the effect varies substantially depending on the type of diversity experience, the type of cognitive outcome, and the study design. Implications for future research and practice are discussed. (Contains 5 notes, 3 tables, and 3 figures.)