The social development model organizes the results of research on risk and protective factors for delinquency, crime, and substance abuse into hypotheses regarding the development of antisocial and prosocial behavior. The model is grounded in empirically supported theories of deviance. It hypothesizes similar general processes leading to prosocial and antisocial development, and specifies submodels for four specific periods during childhood and adolescent development, i.e., preschool, elementary school, middle school, and high school. The phases are separated by major transitions in the environments in which children are socialized; they are not conceived as stages of cognitive or moral development. The theory organizes the evidence regarding risk and protective factors for delinquency and substance abuse by hypothesizing the theoretical mechanisms through which these factors operate to increase or decrease the likelihood of antisocial behavior. Figures, references