ObjectiveThis study investigates the complex interplay between academic self-concept, teacher support, student engagement, and psychological wellbeing among Chinese university students. We aimed to elucidate the mediating role of student engagement in these relationships.MethodsA sample of 597 Chinese undergraduate students from diverse universities participated in the study. We employed structured questionnaires to assess academic self-concept, teacher support, student engagement, and psychological wellbeing. Confirmatory factor analyses and structural equation modeling were used to test our hypothesized model.ResultsStructural equation modeling indicated that the partial mediation model, which considered both direct and indirect effects, outperformed full mediation and direct effect models. Student engagement significantly mediated the relationships between academic self-concept, teacher support, and psychological wellbeing. Importantly, teacher support demonstrated a direct impact on psychological wellbeing, even when accounting for the mediating role of student engagement.ConclusionThis study underscores the pivotal role of student engagement as a mediator in the relationship between academic self-concept, teacher support, and psychological wellbeing among Chinese university students. While student engagement plays a substantial mediating role, our findings also recognize the persistent direct influence of teacher support on psychological wellbeing. These insights have implications for educators and policymakers aiming to enhance the wellbeing of university students by fostering positive academic self-concept and teacher support while recognizing the importance of student engagement.