Objective. This study examines relations among adolescent smoking, parental authoritativeness, parental disapproval of smoking, parental smoking, friends' self-reported smoking, and friends' reports of their parents' authoritativeness. Design. 317 adolescents (12-15 years of age) gave saliva samples and completed questionnaires concerning their own smoking behavior, aspects of their parents' parenting behaviors (used to construct a measure of authoritative parenting), their parents' smoking behaviors, and parental disapproval of smoking. Independent reports obtained from friends were used to calculate measures of friends' smoking and levels of friends' parents' authoritativeness. Results. Higher levels of authoritative parenting and parental disapproval of smoking along with lower levels of parental smoking were associated with a lower likelihood of smoking during adolescence. Friends' smoking was positively associated with adolescent smoking, and it mediated the association between parental smoking and target adolescents' smoking. Friends' parents' authoritativeness did not mediate the association between friends' smoking and adolescent smoking. Conclusions. Along with friends' smoking, parental authoritativeness and parental disapproval of smoking are important influences on adolescent smoking. Consideration of the conjoint influence of the family and the peer group, rather than either in isolation, improves understanding of adolescent smoking behavior.