A cognitive-developmental model postulates three predominant adolescent dispositions (self-definition, social compliance, and affect regulation) which may impede or facilitate transitions in stages of smoking. The purpose of the present prospective study was to build on the findings supporting this model. One hundred schools were randomly assigned to either receive or not receive a social influences smoking prevention program. A baseline survey, including smoking behavior and dispositional items, was administered in the sixth grade in 1990, interventions were delivered in the sixth and seventh grades, and a survey was administered following the seventh grade intervention. Principal component patterns, based on dispositional items, were very similar for grades 6 and 7, did not vary by gender, and the components (rebelliousness, rejection of adult authority, personal dissatisfaction, and peer approval) were correlated. All smoking-stage transitions were positively related to rebelliousness for boys. The relationship of the dispositional scores with smoking-stage transitions was more complex for girls. Receiving the program modified the effects of the dispositional risk scores, particularly for girls.