Background: Although a significant amount of literature has explored peer sexual harassment in higher education, little is known about peer sexual harassment in primary and middle school. Among existing studies, most have examined individual student characteristics that predict peer sexual harassment without considering the importance of the classroom and school context, which may prevent or promote such harassment. Objective: The purpose of this study was to identify individual and school-related factors predicting sexual harassment victimization. Methods: A sample of 17,364 Chilean students from Grades 5 through 8 in 405 schools with low socioeconomic status answered instruments concerning peer sexual harassment, other types of peer victimization and discrimination, and perceptions of classroom and school climate and norms against sexual harassment. Data were analyzed through hierarchical multivariate regression. Results: Experiences of being sexual harassed by other students were reported by 13.5 % of students, with higher frequencies in male students, students from Grades 5 and 6, and students with lower individual socioeconomic status. School-related experiences of being discriminated against due to sexual orientation, ethnic origin, and disability were the strongest predictors of sexual harassment victimization. Conclusion: We discuss how peer sexual harassment might be understood as a consequence of peer social discrimination based on sexism, racism, and ableism. We also discuss the need to provide inclusive school climate policies that allow all students to feel safe and included.