Background: Difficult social interactions with students are reported to be among the main stressors of beginning teachers, and although social competence has been suggested to represent a vital resource for their transition into practice and early-career adaptation, this assumption has rarely been empirically studied. Aim: We conducted two studies to investigate the predictive validity and development of prospective and beginning teachers' social competence. In Study 1, we examined, whether social competence predicts beginning teachers' emotional exhaustion. Study 2 investigated whether university teacher training contributes to social competence development among prospective teachers. Sample: The samples of both studies are based on large-scale assessments. Participants in Study 1 were 1,758 beginning teachers who had been tracked since their entry into university teacher training. Study 2 included 831 prospective teachers who were surveyed over a total period of two years. Methods: Data were analysed utilizing a structural equation modelling approach (Study 1) and latent change score modelling (Study 2). Results: The results of Study 1 revealed that social competence negatively predicts emotional exhaustion. Further, beginning teachers' reports of classroom management functioned as a mediator within that relationship. According to the findings in Study 2, prospective teachers showed no significant enhancements of social competence within one year of university teacher training. However, there was a significant change considering the two-year interval. Conclusions: Social competence, as a predictor of occupational well-being, may constitute one important resource for the early-career adaptation of beginning teachers. However, efforts to promote social competence within university teacher training should be increased.