Background: Conrurrent alcohol and tobacco use may increase the risk for substance abuse in adolescents. The aim of this study was to investigate concurrent alcohol and cigarette use and the co-occurrence risks of each substance in school-going adolescents in Korea. Methods: In a cross-sectional nationally representative survey in 2016, 65,528 students (Mean age = 15.1 years, SE = 0.02) responded to a questionnaire that included measures of substance use and substance use exposure. Results: In all, 13.3% of the students were concurrent lifetime smokers and drinkers (19.3% among boys and 6.7% among girls), 25.5% lifetime alcohol users only (24.2% among boys and 26.9% among girls), 3.0% lifetime smokers only (4.7% among boys and 1.1% among girls) and 58.3% never smoked and never used alcohol (52.2% among boys and 47.8% among girls). All measures of more intensive smoking pattern and smoking exposure and more intensive drinking pattern and drinking exposures, respectively, were associated with consistently increased risk of lifetime alcohol use and lifetime smoking, respectively, compared to lifetime never smokers and abstainers. In multinomial logistic regression, compared to students who neither had used alcohol nor tobacco, concurrent lifetime smokers and drinkers were more likely to be male, mixed or boys school, higher school grade, lower paternal and maternal educational level, perceived lower socio-economic status, ever drug user, perceived stress above average, depressive mood, experience of violence victimization, and living in a rural area or medium sized city. Conclusion: Prevention and treatment strategies should better incorporate the comorbidity of cigarette smoking and alcohol use in their intervention programmes.