PURPOSE: This study was conducted to identify factors for smoking middle school students' intention to quit smoking on the basis of the social influence and self-efficacy [ASE] model. METHODS: Data were collected from 2,015 students from five middle schools in Daegu with a structured questionnaire in March, 2013 and analyzed by using chi2-test, ANOVA, pearson's correlation and multiple regression analysis. RESULTS: The smoking rate was 6.1% among the total subjects and 85.4% of the smokers had intention to quit smoking. The mean value of attitude toward quitting smoking was 2.15+/-0.34, that of social influence 3.38+/-0.65, and that of self-efficacy 2.84+/-0.95. The multiple regression analysis showed an explanatory power of 24.7%, and experience of trying to quit smoking was the strongest factor affecting the intention to quit smoking (beta=.34, p<.01), followed by school years and social influence. CONCLUSION: In order to increase smoking middle school students' intention to quit smoking, intervention strategies are needed to increase positive social influence or to offer public information to younger smoking students in low school years.