Effective sexually transmitted infection (STIs)/HIV prevention programs are urgently needed, but translating evidence-based methods of STI/HIV prevention into sustainable programs has been difficult. Social influences are critical for establishing condom use norms. This study systematically reviewed social network-based interventions focused on condom promotion. Social networks were defined as groups who self-identified prior to the research study. Eleven eligible research studies were identified and included in this review. Only three studies measured biological endpoints and five studies used validated measures of condom use. Among the nine studies with control groups, eight showed significant improvements in at least one measure of condom use. There were large differences in how social network members were identified and involved in the interventions. This systematic review highlights the potential utility of social network-based condom promotion programs. More research is needed to show how these promising studies can be expanded.