There is a need to study the relationship between adolescent bullying attitudes and school bullying behavior to reduce instances of bullying in schools. Based on the Program for International Student Assessment 2018 (PISA 2018), this study investigated the relationship between adolescent bullying attitudes towards different roles and school bullying behavior. Among 34 OECD countries, it also studied the mediating roles of student cooperation and competition, and adolescent bullying attitudes based on gender, grade, and whether one was a bullying victim. We adopted the Coarsened Exact Matching (CEM) method to control the effects of confounders on evaluation results. Overall, the results showed that bullied adolescents' attitudes towards bullying followers and non-bullied adolescents' attitudes towards bullying bystanders and defenders were more positively associated with school bullying behavior. Student cooperation partially mediated this relationship and student competition played the suppressor. The findings also provided fresh insights into anti-school bullying campaigns and practices.