Adolescents, as the fastest growing group of smokers, have been a focus and concern of health educators and researchers. Adolescent smoking is of particular interest because initiation and early habits are known to have important implications for lifetime smoking or cessation. Despite the well-known centrality of the peer group in adolescent behavior, smoking cessation programs have been largely directed toward individuals rather than groups, with emphasis on encouraging the individual to say "no." In this paper, smoking behavior and peer group patterns among a sample of 1,689 Grade 8 students from southern Ontario were analyzed to ascertain possible patterns of indirect influence by friends and acquaintances. Gender differences also were assessed. It was found that peer groups are crucially important in the initiation of smoking among young adolescents, particularly females. The patterns of indirect peer influence on girls is such that girls are less likely to stop smoking once they have begun than are boys.