This study examines the independent, relative, and additive associations between both parent and peer role models and longitudinal patterns of smoking across adolescence and early adulthood. An analysis of data from the National Longitudinal Study of Adolescent to Adult Health (N = 10,166) reveals at least four distinct trajectories of smoking across ages 13 to 35 years: (1) nonsmokers; (2) late peak (almost 10 cigarettes per day around age 30); (3) an early peak group that reached roughly 10 cigarettes per day around age 20 and declined; and (4) a high group that increased during adolescence and early adulthood and then remained high. Parent and peer smoking behaviors were associated with trajectory group membership net of controls for sociodemographic characteristics, parental socioeconomic status (SES), parent-child relations, and the availability of cigarettes in the family home. Parents and peers appear to have at least some independent associations net of each other, but their combined effects are powerful.