This study investigate the mediating effects of academic self-efficacy on the relationship between academic stress and academic burnout of Korean adolescents. A survey was conducted using a convenient sample drawn from 850 students from nine junior high schools in Kunggi-do Province. Data were analyzed using SAS package program. The results show that many students were dissatisfied with their own academic performance. There was a significant positive relationship between academic stress and academic burnout. In particular, academic performance and studying had a significant interaction effect on academic stress. Academic self-efficacy had negative effects on academic stress and academic burnout. Academic self-efficacy partly mediated the relationship between academic stress and academic burnout. These results suggest that improving academic self-efficacy is crucial for preventing and reducing symptoms of academic stress and academic burnout. In this regard, continuous social support and efforts are needed to develop instructional strategies and educational programs that can improve the academic self-efficacy of adolescents.