The article focuses on three sociopsychological variables concerning adolescent substance use: (1) structural (i.e., the adolescents' social environment and position in society); (2) social-interactional (i.e., the quality and influence of interpersonal relationships), and (3) attitudinal (i.e., individual or group-shared attitudes conducive to substance use). Among the structural variables, age, sex, race, and the location and size of the community or residence are found to be significantly related to drinking or drug abuse; social class tends not to be related to drinking but to the use of other substances. Among the social-interactional variables, parental and peer influence are the most significant determinants of not only abstinence or drug/alcohol use but also the pattern of use and attitudes towards drinking/drugs. Researchers have isolated three major types of attitudinal variables: (1) attitudes towards the substances themselves, (2) alienation, and (3) locus of control (i.e., whether or not individuals believe they can control events in their lives). Despite incompleteness and inconsistency, the facts presented here are supportive of a social learning theory approach to the subject, that is, the entire process of abstinence, use, and abuse is normally learned behavior and a function of differential reinforcement. The area in which the state of the field is still most in need of development is in offering and empirically validating theoretical explanations of adolescent substance use. The article includes 95 references.