Objective  To explore the association between sexual orientation and school bullying behaviors among senior high school students.

  Methods  Using multistage stratified cluster sampling, we recruited 4 015 urban and rural students from 16 senior high schools in 4 municipalities across Hunan province; then we carried out a survey on sexual orientation and school bullying behaviors among the students with a self-designed questionnaire from April to July, 2018.

  Results  Of all the students, 78.9%, 3.7%, 2.0%, and 15.4% reported their heterosexual, bisexual, homosexual, and uncertain sexual orientation, respectively. The reported frequency of school bullying victimization and perpetration were 13.0% and 5.0% and the frequencies differed significantly by sexual orientation among the students. Logistic regression analysis indicated that the students reporting bisexual, homosexual, and uncertain sexual orientation were more at a higher risk of school bullying victimization, with the odds ratio (OR) (95% confidence interval 95% CI) of 1.650 (1.012 – 2.692), 1.799 (1.010 – 3.202), and 1.438 (1.106 – 1.869) compared to those reporting heterosexual orientation; while, the students with heterosexual orientation were more likely to have school bullying perpetration (OR = 4.284, 95% CI: 2.319 – 7.914) in comparison with the students with other sexual orientation.

  Conclusion  There is an association between sexual orientation and school bullying behaviors among senior high school students and the students with homosexual orientation are at higher risk of both school bullying victimization and perpetration.