This 1-year prospective study of 173 families with two or more children examines the influence of parent, sibling, and peer modeling (i.e., use) and attitudes on adolescent use of alcohol. Independent questionnaire data were obtained from the adolescent, father, mother, and sibling(s). Structural equation modeling methods were employed to examine these relationships. Parent attitude toward youth alcohol use and parent modeling of alcohol use were strongly related to change in adolescent alcohol use, suggesting that parents can influence the future use of alcohol by their children. Peer and sibling modeling and peer attitudes also influenced adolescent alcohol use.