Background: Health is essential for the sustainable well-being, yet high stress, anxiety, and lack of sleep among Korean adolescents have become significant social concerns.Methods: This study examined the impact of stress on anxiety and investigated whether sleep time mediates this relationship in 46,870 male and female adolescents, ranging from first-year of middle school students to third-year high school students. Data were obtained from the "18th Korea Youth Risk Behavior Survey" conducted by the Korea Disease Control and Prevention Agency.Results: The analysis showed that increased stress was associated with reduced sleep time and higher anxiety levels, stress was found to heighten anxiety, partly by reducing sleep time.Conclusions: Based on these findings, the study recommends: ① developing mental health indicators to quickly identify adolescents at risk for mental health issues, ② encouraging cooperation between schools, government agencies, healthcare providers to enhance access to mental health programs for adolescents, and ③ implementing policies that promote healthy behaviors, ensure adequate sleep, and improve overall well-being.