Adolescent athletes often face challenges that impact their mental health and sleep quality, including the need to adjust to irregular training schedules, intense training, and competitive pressures. Therefore, the present study aimed to investigate the prevalence of sleep and mental health problems and their relationships with perceived stress in Iranian adolescent athletes. The research design was a cross-sectional study. Adolescent athletes (N = 579, aged 13 to 18 years) were selected from eight different team and individual sports, including wrestling, basketball, volleyball, karate, futsal, handball, and football. Three scales were used to collect data: the Cohen Perceived Stress Scale (PSS-14), Pittsburgh Sleep Quality Index (PSQI), and General Health Questionnaire-28 (GHQ-28). The results showed high levels of sleep disturbance (54.2%), mental health problems (54.7%), and perceived stress (48.7%). The results also showed significant positive correlations between perceived stress and mental health symptoms (r = 0.35) and between sleep disturbance and mental health symptoms (r = 0.39). These findings suggest an association between sleep quality, perceived stress, and mental health in adolescent athletes.