<p>Peer bullying poses a serious risk to adolescents’ psychosocial development and school adjustment. However, culturally adapted and evidence-based intervention programs remain limited in non-Western societies. Restorative justice approaches provide an alternative to punitive discipline by emphasizing relationship repair, accountability, and empathy development. This study examined the effects of a 12-week multi-component Restorative Justice Program implemented with students aged 12–13 in Istanbul, Türkiye, on peer bullying behaviors and restorative justice orientations. A quasi-experimental design was used, including an experimental group of 25 students and a control group of 20 students. Participants completed pre-test and post-test assessments, while the experimental group also completed a four-week follow-up assessment. Findings indicated a significant increase in empathy levels within the experimental group. Strong improvements were also observed across all subdimensions of restorative justice orientation. Within-group analyses revealed significant reductions in verbal bullying, property damage behaviors, and total bullying perpetration. In between-group comparisons, the most robust post-intervention difference was found for empathy after statistical corrections. Follow-up results suggested that these gains were maintained in the short term. Overall, the findings provide preliminary evidence that a culturally adapted and structured restorative justice program may be effective in increasing empathy and reducing bullying behaviors at the classroom level. In particular, attitudinal change appears to be an accessible proximal target for restorative justice-based interventions. Nevertheless, the results should be interpreted cautiously due to the small sample size, lack of random assignment, and baseline group differences. Future research should replicate these findings using larger samples and randomized controlled designs.</p>