BACKGROUND: The purpose of this the study was to investigate the findings of previous research studies that focus on the effectiveness of school-based interventions on childhood and adolescent obesity. METHODS: Initially, 1,617 studies that were conducted in South Korea, United States, United Kingdom, Spain, Australia, and New Zealand were collected. Finally 14 studies were selected for a systematic review of literature and meta analysis. RESULTS: The findings of the present study suggest that school-based physical education has had a positive impact on students' obesity. However, calculated Effect Size (ES) from the meta analysis shows that the impact of school-based physical education was not significant. CONCLUSION: According to this study, we may conclude that it is necessary to reform the physical education curriculum in schools to improve the effectiveness of preventing obesity.