Our Family, Our Voices: An Efficacy Trial Of An Intervention Utilizing Family-Based Assets To Optimize HIV Prevention And Care Outcomes For Black Sexual and Gender Minorities In House Ball Communities - Originating within urban Black and Latinx communities, the House Ball Community (HBC) is a gender- and sexuality expansive population facing overlapping hardships such as stigma and family rejection that contribute to their overrepresentation in the HIV epidemic. The HBC population, estimated at 8,000 nationwide, is concentrated in New York City (NYC) with growth in the US South and includes a large proportion of Black Gender and Sexual Minority (BGSM) individuals, primarily Black and Latinx gay men who have sex with men (MSM) and transwomen and men. BGSM remain deeply impacted by the US HIV epidemic, with low uptake of pre-exposure prophylaxis (PrEP) and limited HIV care engagement due to stigma and systemic barriers, particularly in the US South. Despite the HBC’s longstanding role as a site for advocacy and normative change within the broader BGSM community, the HBC has received minimal targeted HIV treatment/prevention efforts and remains severely understudied. Our Family, Our Voices (OFOV) addresses these gaps through a community-driven, HIV status-neutral, gender-expansive, group-level intervention developed in collaboration with the HBC. Leveraging the HBC’s hierarchical family structure (e.g., house mother, house father), OFOV’s intervention format includes a family-based retreat for HBC members to empower them to advocate for their own health, cultivate leadership skills, and improve clinical outcomes. OFOV builds on core elements of Many Men, Many Voices (3MV), the only CDC “best evidence” intervention for Black gay MSM that has demonstrated increased HIV testing rates. Previously adapted in NYC (R34 MH124082), OFOV has shown feasibility, but further research in a powered study is needed to evaluate efficacy and scalability across 3 areas, including NYC: Aim 1 (pre-intervention phase): Tailor OFOV materials to local contexts through collaborations with indigenous Black gay CBOs in Atlanta and Dallas. Aim 1 (intervention phase): Conduct a cluster-randomized stepped wedge trial with 27 HBC houses (≥ 20 members each) to evaluate OFOV’s efficacy. Primary outcomes include engagement and retention in HIV prevention (testing, PrEP) and care (antiretroviral therapy (ART), viral suppression) at baseline, 3, 6, and 12-months post-intervention, with 24- and 36- month maintenance periods. Hypotheses include increased leadership skills and HIV-related self-efficacy. Aim 2 (post-intervention phase): Use a mixed-methods approach to identify contextual factors influencing OFOV adoption and implementation. Aim 2 (post-intervention phase): Explore how leadership training impacts community norms and behaviors, hypothesizing high acceptability and adaptability across geographic and cultural settings. The NIMHD framework will guide qualitative work (in Aims 1 and 2) with HBC members and house leaders (directly exposed and unexposed to OFOV) to assess individual, interpersonal, and community-level barriers and facilitators to sustainability. Collaborations with HBC leaders, CBOs, and a multidisciplinary team will ensure cultural relevance, sustainability, and implementation feasibility across jurisdictions.