This study examined psychosocial factors influencing smoking intention in Korean male middle school students. We used a descriptive cross-sectional design, based on the biopsychosocial model, to analyze data from 309 male adolescents aged 14–16 years in middle school. Of the psychological factors examined, stress and risk-taking tendency were significantly associated with smoking intention. Of the social factors examined, social normative beliefs, close friends’ and siblings’ smoking, and low socioeconomic status were significant factors in smoking intention. The explanatory power of these variables in the predictive model was 23.1%. In conclusion, the unique psychological and social characteristics of adolescents should be reflected in interventions for smoking prevention.