The current study assessed 3 hypothesized mediating mechanisms underlying the relation between parental alcoholism and adolescent substance use. Using structural equation modeling, we analyzed data obtained from a large community sample of adolescent children of alcoholics and a demographically matched comparison group. Results suggested that parental alcoholism influenced adolescent substance use through stress and negative affect pathways, through decreased parental monitoring, and through increased temperamental emotionality (which was associated with heightened negative affect). Both negative affect and impaired parental monitoring were associated with adolescents' membership in a peer network that supported drug use behavior. The data did not support a link between parental alcoholism and temperamental sociability.