Adolescent smoking has been widely studied, but surprisingly little research has been done about the reasons given for smoking by adolescents themselves. This study examines the reasons given by Finnish adolescents for their own smoking and the reasons that they perceive for smoking by others. It reports on how these reasons have changed over a period of 15 years. In 1984, a questionnaire about reasons for smoking was administered to a sample of adolescents aged 14-16 (N = 396). The questionnaire was administered again to a similar sample (N = 488) in 1999, when Finland adopted strict new tobacco legislation. It was found that the reasons given (i.e., attributions) had changed considerably, and that the attributions for the adolescents' own behavior were quite different from the attributions for smoking by others. The attributions were only weakly influenced by the participants' gender or by their smoking habits, either in 1984 or 1999. In relation to participants' own smoking, the later questionnaire elicited inner subjective experiences involving "good feelings." In relation to the perceived reasons for other people's smoking, it elicited more responses connected with the notion of "belonging." The limitations of the study and suggestions for further research are discussed.