The smoking attitudes and behavior of two samples of British 15-year-olds (N = 278) were studied by questionnaire. “Smokers” (anyone who had smoked at all within the previous week) held less negative attitudes about smoking, were more likely to have a father who smoked, and anticipated less parental disapproval of their smoking. When asked to name their five best friends among their classmates, smokers were more likely to name other smokers than were nonsmokers. On the basis of these results, we argue that the notion of “peer group influence” should be reconceptualized in terms of intergroup processes and social identity concerns within the peer group.