The role of family structure in adolescence has been linked to a host of problem behaviors, including marijuana use. This paper investigates the relationship between family structure and marijuana use, and elaborates previous research by 1) exploring several intervening mechanisms that affect the relationship, and 2) examining the effects of a variety of family forms. Analyses of data from the National Youth Survey (1977-79) indicate that 1) a parental divorce or living with a stepparent decreases family attachment among adolescents; 2) attenuated family attachment and involvement increase the likelihood of associating with drug-using peers; and 3) less family involvement and increased associations with drug-using peers increase the probability of initiating marijuana use and elevate frequency of use.