Abstract Body (Do not enter title and authors here): Background: Cigarette smoking has been linked to sleep problems in both adults and adolescents. Some recent studies suggest dual users of conventional cigarettes (CC) and e-cigarettes (EC) may be more likely to experience sleep problems compared to CC-only users. Given the shorter sleep duration observed among South Korean adolescents compared to their global peers, this study investigates the relationship between smoking status and sleep health in Korean adolescents aged 13-18. Methods: We analyzed data from the 16th to 19th Korea Youth Risk Behavior Survey, a cross-sectional annual survey of health risk behaviors among Korean middle and high school students conducted from 2020 to 2023. The sample included 195,636 participants who reported sleep duration and satisfaction. Participants were categorized into five groups based on tobacco use: non-users, former users, current CC-only users, current EC or heated-tobacco product (HTP)-only users, and current dual users (CC+EC or CC+HTP). Sleep health was assessed using self-reported questionnaires on sleep duration during weekdays and overall sleep satisfaction: ‘<7 hours & Insufficient’, ‘≥7h & Insufficient’, ‘<7h & Sufficient’, and ‘≥7h & Sufficient’. Adolescents categorized as experiencing ‘Short (<7 hours) & Insufficient’ sleep were considered to have the poorest sleep health. We conducted a multinomial logistic regression analysis to explore the association between sleep health and smoking status. Covariates adjusted for the analysis included gender, grade, year, economic status, residential status, academic achievement, self-rated health, perceived stress, and smartphone use. Results: Of 195,636 adolescents, 41.2% of girls and 27.6% of boys experienced ‘Short & Insufficient’ sleep. Current dual users of CC and EC or HTP had the highest prevalence (52.7%) of experiencing ‘Short & Insufficient’ sleep compared to other smoking groups. Compared to non-users, the odds ratio (OR) for ‘Short & Insufficient’ sleep was significantly highest in the current dual users (OR 2.37, 95% CI 2.10-2.67). Current CC-only users, current EC or HTPs-only users, and former users had ORs of 2.08 (95% CI 1.85-2.34), 1.74 (95% CI 1.34-2.25), and 1.77 (95% CI 1.50-2.10), respectively. Conclusions: Our findings suggest that current smoking and dual use of tobacco products are associated with poor sleep health among Korean adolescents. Implementing smoking cessation programs may contribute to better sleep quality in this population.