The goal of this study was to determine how family functioning influences the onset of adolescent cigarette smoking and how family functioning and parental smoking together influence adolescent smoking. A 6-year prospective design was used to follow a group of 508 families with a child aged 11-13 years. Predictor measures were parents' smoking status at Time 1, parents' scores on scales measuring family cohesion and parent-adolescent strain, and adolescents' scores on 3 scales measuring psychological adjustment. Results showed that poorer family functioning predicted subsequent adolescent smoking, independent of other measured factors. The strongest predictions were yielded by the combination of low family cohesion and parental smoking, with early adolescents who had a parent who smoked and low family cohesion reporting more than twice the rate of smoking in late adolescence.