The present study examines growth curve trajectories of cigarette and alcohol use from 13 to 19 years, and investigates how family relations (i.e., decision-making opportunities, negative family interactions, and positive identification with parents) relate to contemporaneous and predictive alcohol and cigarette use during adolescence. Data came from a longitudinal study of European American and African American families from a range of socioeconomic backgrounds (n = 1160 for alcohol use; n = 1102 for cigarette use). European Americans had higher levels and faster rates of alcohol and cigarette use than African Americans. European Americans females had the greatest likelihood of increased cigarette use. Negative family interactions and positive identification had contemporaneous and predictive associations with alcohol and/or cigarette use. Negative family interactions were related to increased smoking and drinking, whereas positive identification was associated with decreased use. Family relations differentially affected cigarette use according to ethnicity and gender, but had similar effects on alcohol use. (Contains 4 tables and 2 figures.)