The social environment plays a critical role in determining the likelihood that an individual will use drugs or will develop a drug use disorder. Recent evidence obtained from preclinical studies reveals that proximal social factors (i.e., those factors that are immediately present at the time of drug exposure) exert a particularly strong influence on both drug-seeking and drug-taking behavior. These studies are advancing our understanding of the role of the social environment in drug use by showing that the rewarding and reinforcing effects of drugs depend on (a) whether other individuals are immediately present and (b) whether those individuals are also using drugs. Furthermore, the preclinical literature examining the role of social learning in behavior maintained by nondrug reinforcers reveals a number of behavioral mechanisms by which social contact may influence drug use, as well as potential ways the social environment may be modified to prevent or reduce drug use. Additional research is needed to determine potential age and sex differences in the effects of social contact on drug use, to determine the generality of the current findings across different pharmacological classes of drugs, and to determine the role of social contact on drug intake during different transitional stages of drug use disorders; however, enough evidence now exists to begin implementing social interventions in clinical and at-risk populations.