Background: The feminization of school hypothesis suggests that boys underachieve in school compared to girls because school rewards feminine characteristics that are at odds with boys' masculine features. Aims: The feminization of school hypothesis lacks empirical evidence. The aim of this study was to test this hypothesis by examining the extent to which school demands are actually associated with female more than male students. Sample and method: A large sample of 1,954 students (1,115 girls and 839 boys) from grades seven, nine, 10, and 12 took part in the study. The participants were asked to rate the extent to which various characteristics valued in the school setting were exhibited by girls or boys who succeed in school. Results: Three sets of characteristics related to school success emerged from the analyses: compliance, assertiveness, and effort/intelligence. Compliance and effort/intelligence were associated with the girls more than with the boys, while assertiveness was associated with the boys more than with the girls. Conclusion: The feminization of school hypothesis received weak support. This study discusses the limits of this hypothesis to explain boys' underachievement in comparison with girls.