This research aims to analyse the complex connections between students' engagement in extracurricular activities (ECAs), their sense of school belonging, and the cumulative effects on their psychological well-being and academic performance. The results based on a sample of 892 students reveal that active engagement in ECAs does not influence students' academic outcomes directly. Instead, the benefits derived from ECAs primarily manifest in non-academic spheres, particularly in enhancing well-being. Moreover, ECAs yield positive psychological well-being and academic performance only when students have a low sense of school belonging. At higher levels, the positive impact of ECAs diminishes, and it may even detrimentally affect academic performance. This study offers a different viewpoint to address the dilemma surrounding ECAs and practical implications in the development of institutional policies.