What Works Against Peer Bullying? A Meta-Analysis of School-Based Interventions in Türkiye

Peer bullying remains a persistent global concern with far-reaching implications for students’ psychological, social, and academic development. While numerous interventions have been developed to address this issue, their effectiveness within culturally specific contexts warrants further investigation. This meta-analysis synthesizes 35 empirical studies conducted in Türkiye, encompassing 1,534 participants aged 4 to 17. Using a random-effects model, the findings indicate that intervention programs are associated with reductions in bullying (ES = 0.78) and victimization (ES = 0.74) and improvements in social skills (ES = 0.62) and well-being (ES = 0.83), although effects varied across studies and should be interpreted in light of between-study heterogeneity. Exploratory moderator analyses suggested that effects were associated with educational level and participant type for bullying, and with theoretical background for victimization; however, these subgroup patterns should be interpreted cautiously given the limited number of studies in some categories and the fact that moderators were examined in separate models. In exploratory univariable meta-regression analyses, session duration was associated with bullying effect sizes, whereas the number of sessions was not. These results underscore the importance of developing comprehensive, theoretically informed, and culturally responsive anti-bullying strategies, while also suggesting potential mechanisms and boundary conditions that may inform the adaptation of such interventions beyond the Turkish context. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2026.