For adolescents, body weight can be a complicated and sometimes difficult issue. Though the majority of adolescents report being aware of normative gendered body ideals, how adolescents incorporate or reject these ideals into their own weight-control decisions or sense of self can vary dramatically, largely in reaction to their social experiences with body ideals in the local, immediate contexts of their daily lives. The role of one such local context - schools - has remained largely unexplored in existing literature. Using the National Longitudinal Study of Adolescent Health (Add Health) and multi-level modeling, I investigate the role high school weight cultures play in the development of adolescents’ weight-loss behaviors, overweight self-perceptions, and self-esteem. I employ social comparison theories, specifically the idea of who may serve as a likely target for social comparison - general others, similar others, or high status others - to develop hypotheses about which aspects of the school context may be associated with various aspects of adolescents’ body weight. Overall, my results indicate that there is a strong relationship between adolescents’ weight-loss behavior, self-perception and self-esteem and the weight-related culture in the school. For example, adolescent boys, on average, are significantly less likely to report perceiving themselves as overweight or engaging in weight-loss behaviors when they attend schools where there are many overweight boys in the student body. I also find that there is some variation within the school in terms of which peers are most salient to adolescents’ behaviors and self-perceptions. Both boys and girls are particularly impacted by the values and behaviors of similar others, when similarity is defined by same-sex adolescents of a similar body size. For example, on average, overweight adolescent girls are significantly more likely to report engaging in weight-loss behaviors when a higher proportion of overweight girls in their school also are engaged in weight-loss behaviors. The same pattern is found among adolescent boys. Overall, these findings suggest that meso-level social contexts - like schools - may be particularly important to how individuals incorporate macro-level beliefs or values - like gendered body ideals - into their own behaviors and self-concepts. / text