Objective: The authors' aim in this study was to determine, after adjustment for the effects of body mass index and socio-demographic measures, whether sex-specific weight control norms would have significant independent relationships with the weight control behavior of college women and men. Participants: The authors used an anonymous questionnaire to assess a sample of 470 college students, aged 18 to 26 years, attending either a 2- year community college or a 4-year public university. Methods: To calculate body mass index, the authors objectively measured the height and weight of each participant. They conducted separate discriminant function analyses for women and men. Results: The discriminant function analyses clearly indicated that weight control norms of same-sex, close friends were the best discriminators of involvement in weight control. Conclusions: The findings indicate that perceived peer norms may be important but overlooked risk factors for engaging in unhealthy weight control practices. The authors discuss the implications of these findings in the context of student health promotion. (Contains 3 tables.)