The Social Stress Model of Substance Abuse builds upon and integrates knowledge from numerous psychosocial theories and models. According to this model, the likelihood of an individual engaging in drug abuse is a function of the stress level and the extent to which it is offset by stress modifiers such as social networks, social competence, and resources. This article synthesizes current empirical evidence for this model. Thirty-five primary research studies are described, with special attention to the four psychosocial constructs inherent in the model: stress, social networks, social competence, and resources. Consistencies and inconsistencies in the findings, a critique of key methodological issues, and suggestions for future research are provided. © 1993 John Wiley & Sons, Inc.