Background <p>This study examines the impact of academic burnout on adolescents’ psychological and social well-being, emphasizing the role of optimism as a mediator in this relationship. The aim is to understand how burnout influences these dimensions to inform targeted interventions that promote resilience and mental health in educational contexts.</p> Methods <p>A cross-sectional study was conducted with 1,092 adolescent students (53.5% female, aged 12–17 years, M = 14.5, SD = 1.11) from six schools in Almería, Spain. Participants were selected through a cluster-based random sampling method and completed the Maslach Burnout Inventory-Student Survey, Ryff’s Psychological Well-Being Scale, Keyes Social Well-Being Scale, and the Optimism-Pesimism Questionnaire. Descriptive, correlational, and mediation analyses were performed using SPSS and the PROCESS macro.</p> Results <p>High levels of academic burnout were associated with significantly lower psychological and social well-being, as well as reduced optimism. Optimism was found to partially mediate the relationship between academic burnout and well-being, accounting for its negative associations with both psychological and social dimensions.</p> Conclusions <p>These findings highlight the role of optimism as a mediator in the relationship between academic burnout and adolescents’ well-being. The study underscores the need for intervention strategies that focus on promoting optimism to reduce burnout and enhance mental health in educational settings. Future research should further explore these dynamics across different educational stages and cultural contexts.</p>