Sexist attitudes are rooted in patriarchal structures,which uphold traditional gender stereotypes, and which are still found in society today. Scholars have found gender differences in perceived academic achievement, with girls performing better than boys, and negative relationships between sexism and perceived academic achievement. Moreover, perceived academic achievement and sexist attitudes have been associated with aggression and different kinds of violence. This study examined the associations between sexist attitudes and perceived academic achievement (using self-report data). The study also assessed the mediating role of physical and verbal aggression in the relationship between sexist attitudes and perceived academic achievement. Seven hundred eight Spanish adolescents participated in the study. The mean age was 13.00 (SD = 0.95; range = 12-14 years). Structural equation modelling (SEM) was used to analyse the effects among variables for boys and girls. Results showed the role of benevolent sexism and hostile sexism in perceived academic achievement, as well as the mediating role of aggression in the relationship between sexism and perceived academic achievement. Findings and implications are discussed to assess measures for establishing intervention programs and educating adolescents in a non-sexist manner. Keywords: hostile sexism; benevolent sexism; perceived academic achievement; physical and verbal aggression; adolescence