College students often affiliate with similar peers, forming identity-based peer crowds. Research has shown that affiliations with certain peer crowds is associated with risky behaviors, thus derailing college success. This study examined whether college peer crowd affiliations predicted risky and prosocial behaviors. Participants were 527 students at a public university in the Midwest (aged 18 - 26). Hierarchical multiple regression analyses showed that Counterculture and Athletic/Social affiliations positively predicted risky behaviors. Arts/Ethnic and Scholastic affiliations positively predicted prosocial behaviors and negatively predicted risky behaviors. In addition, hierarchical multiple regression analyses showed that gender moderated the relation between peer crowd affiliation and prosociality. The results highlight the importance of college peer crowds and their implications for academic success. The discussion focuses on ways to promote positive behavior among college peer crowds using research.