Purpose: The purpose of this study was to examine the effects of a smoking cessation program using self-regulated learning strategy as an approach for middle-school boys to stop smoking. Methods: A one group time series study was utilized for the purpose of this study. A five-week smoking cessation program, based on the self-regulated learning strategy of Zimmerman (1989), was provided to 15 middle-school boys who were smokers. Data were collected from July to September, 2008 and analyzed using descriptive statistics, repeated measures ANOVA, and non parametric test, Friedman, 2 related samples with SPSS/WIN 14.0 program. Results: Following the intervention, the participants showed significant differences on self-regulatory efficacy, cons of smoking, stage of smoking behavior change, nicotine dependency, urine cotinine levels, and CO expiration levels compared to those at pretest and those differences remained at 5 months after the intervention, except cons of smoking. Conclusion: This study suggest that the smoking cessation program using self-regulated learning strategy is effective for smoking cessation in middle-school boys and those smoking cessation behaviors remained for up to 5 months after the completion of the intervention. Broad application of the program would be beneficial for teenagers who smoke.