Reflected self-appraisal suggests that individual functioning is related to the fit between individual characteristics and the norms of their primary contexts. To apply this social psychological concept to the study of obesity, we hypothesized that adolescents at risk of obesity would have lower academic achievement overall than other students, especially in schools in which their weight status was most likely to elicit negative evaluations. Multi-level modeling of nationally representative data revealed that the negative longitudinal association between risk of obesity and achievement was stronger in schools with higher rates of romantic activity and lower average body size among students, two school contexts in which obesity was likely to be stigmatized, but weaker in schools with higher rates of athletic participation, a school context in which such stigmatization was also likely. Additional analyses suggested that this last, unexpected finding reflected a process of niche-picking. (Contains 5 tables.)