Cisgender women face significant HIV risks in the United States yet retention in prevention research is challenging. The same factors that increase HIV vulnerability also create barriers to research participation. This qualitative study explored multilevel barriers and facilitators to retaining cisgender women with increased HIV prevention needs in research using the social ecological model (SEM). Semi-structured interviews were conducted from August 2023 to February 2024 with 114 participants across three groups: HIV-negative cisgender women with increased HIV prevention needs (n = 34), cisgender women living with HIV (n = 40), and HIV prevention/treatment stakeholders (n = 40). Participants were recruited nationally through convenience sampling via social media and organizations. Directed content analysis was used to identify retention factors across individual, environmental, intervention, and structural levels. Barriers included substance use affecting contact maintenance, concerns about study time commitments, frustrations with unclear study procedures, poor staff rapport, safety concerns around intimate partner violence, historical research mistrust, and systemic vulnerabilities like housing instability. Facilitators included creating affirming environments that fostered purpose, flexible scheduling with incremental compensation, clear study expectations and health education/support, authentic staff relationships, discrete communication methods, transparent study procedures and approaches, virtual visit options, and availability of multiple contact methods. Findings corroborated a key paradox: those most vulnerable to HIV acquisition may be least likely to complete longitudinal studies due to structural barriers. Successful retention requires flexible approaches that address barriers at all SEM levels. These findings provide strategies for researchers to improve retention among cisgender women with increased HIV prevention needs, strengthening research representativeness and effectiveness.