The aim of the present study was to assess the combined influence of gender stereotypes, sexism, and homophobia on attitudes toward bullying and bullying behavior. A total of 1,500 Spanish adolescents between 12 and 18 years of age (49.3% girls and 50.7% boys) completed a questionnaire that included measures of bullying, attitudes toward bullying, gender-stereotyped personality traits (instrumentality and expressiveness), hostile and benevolent sexism, and attitudes toward gay men and lesbians. First, the findings demonstrated that boys scored significantly higher on all the variables assessed except on benevolent sexism. Two similar models were obtained for both sexes. Benevolent sexism and, in boys, more positive attitudes toward gay men predicted more negative attitudes toward bullying when mediated by more expressive gender traits. An inverse pattern was also observed: Hostile sexism predicted more favorable attitudes toward bullying when mediated by instrumental gender traits. Attitudes toward bullying were highly correlated with bullying behavior. The five-predictor variables (including attitudes toward bullying) explained 58% of the variance of bullying behavior in girls and 37% of such variance in boys.