Context: E-cigarettes were introduced to support smoking cessation, but their popularity has increased among nonsmokers, challenging current perspectives on their safety and effectiveness as a public health intervention. The objective of this systematic review was to identify and synthesize current evidence on the influence of social factors on e-cigarette intentions and use. Evidence acquisition: MEDLINE, CINAHL, PsycINFO, and Embase were searched for studies of the effects of social factors on e-cigarette intention or use in February 2019. Studies were included if they used experimental, longitudinal, qualitative, or mixed methods designs. Advertising, social interactions, and social norms were considered as social factors; social media was considered a conduit for other social factors. Two reviewers screened all studies; bias risk was evaluated for all RCTs using the Cochrane risk of bias tool. Evidence synthesis: This review included 43 studies: 9 experimental, 11 longitudinal, 22 qualitative, and 1 mixed method. All experimental studies examined advertising and consistently showed that exposure increased intentions to use e-cigarettes. Evidence of the influence of social interactions and social norms came from longitudinal and qualitative studies, suggesting that these factors could increase e-cigarette use. Most participants were nonsmokers (81%; 22,233 of 27,303). Studies rarely considered differences in the effects of social factors on smokers and nonsmokers. Conclusions: Given the increased popularity among nonsmokers and the potential for advertising to increase e-cigarette use, closer public health monitoring of e-cigarette uptake by nonsmokers is warranted. Future primary research should be designed to measure how social factors affect smokers and nonsmokers differently.