This study analyzed longitudinal data from 19 institutions to determine if the net effects of diversity experiences on orientation toward social/political activism and political views are discernible as early as the first year of postsecondary education. Statistically controlling for other influences, including precollege measures of each outcome, we found that interactional diversity positively influenced both social/political activism and liberal political views, and that classroom diversity had a small positive influence on social/political activism. More importantly, however, we also found that the magnitude of the effects of both interactional and classroom diversity is substantially determined by individual student precollege characteristics. (Contains 4 tables.)