Bullying is grounded in the interactions between an individual and complex social-ecological systems. Therefore, bullying involvement is not just confined to the classroom or school. Recent research suggests that sibling aggression may be a predictor for peer-level aggression. These findings may be more relevant for students with disabilities because studies suggest that students with disabilities are disproportionately involved in the bullying dynamic. Therefore, this study explored the intersection between sibling aggression and school belonging on bullying, victimisation and fighting for 14,508 students, including 1183 students with disabilities and 13,325 students without disabilities in grades 6 through 12. As hypothesised, students with disabilities reported higher levels of victimisation, bullying and fighting. Additionally, high levels of school belonging partially buffered fighting and bullying behaviours for students with and without disabilities. These findings demonstrate the importance of establishing an inclusive and safe environment for school-aged youth.