We propose a social network-based PrEP adherence intervention as part of a comprehensive, context-specific approach to HIV prevention for TW in Lima, Peru. In order to be effective, PrEP-based prevention strategies need to address not only biological efficacy, but also individual behavioral decision-making processes, interpersonal partnership contexts of risk, peer norms of sexual behavior and PrEP adherence, and structural access to prevention technologies. Using a health promotion behavioral model that combines Social Action Theory with social network theories of information dissemination and collective behavior change, we propose to develop and refine a network-based intervention that promotes PrEP adherence in the existing social networks of TW. Formative research will outline individual, partner-level, and network-based contexts of sexual risk behavior, patterns of social network interactions, anticipated adoption and use of new prevention technologies, and optimal content for a PrEP adherence intervention. Findings will be used to define the elements of a prevention intervention using social networks of TW and social media technologies to generate, implement, and reinforce social norms of PrEP adherence and risk behavior reduction for TW.