The purpose of this study was to investigate how postgraduate engagement is affected by the sense of belonging, academic self-efficacy and academic hardiness. The validated self-reported scales were used to survey 308 postgraduate students in Mainland China who had taken distance learning courses. The proposed research model exhibited high predictive performance, confirming the established 10 hypotheses. The results indicated that sense of belonging positively and significantly influenced academic self-efficacy, academic hardiness and postgraduates' emotional engagement. Academic self-efficacy and academic hardiness had a positive and statistically significant impact on postgraduates' cognitive, emotional and behavioural engagement. Therefore, sense of belonging directly impacted postgraduates' emotional engagement and indirectly impacted postgraduates' cognitive and behavioural engagement. We also found a significant mediation effect of academic self-efficacy and academic hardiness in distance learning courses. Overall, our proposed research model revealed the influence mechanism of sense of belonging, academic self-efficacy and academic hardiness in postgraduate engagement in distance learning courses. These factors need to be considered when designing and implementing distance learning courses, teachers and researchers need to be aware of these interdependencies in order to maximize learning effects in the distance learning environment.