PROJECT SUMMARY/ABSTRACT By 2030, approximately 73% of people living with HIV (PLWH) in the U.S. will be older than 50 years. Age 50 is a benchmark age in HIV-geriatrics care because HIV accelerates aging via the processes of chronic inflammation and immunosenescence. Loneliness and social isolation are common among older adults, but our preliminary research and emergent evidence with older PLWH show that older PLWH desire social connections with other older PLWH that do not require disclosure of HIV-status and that help them regain a sense of control and purpose in living a fulfilling life with HIV. Group singing creates social opportunities that are linked to improved psychosocial wellbeing in older adults, thus holding tremendous potential for older PLWH. Group singing improves psychosocial wellbeing via increased feelings of belonging and social bonding, although less is known regarding how group singing impacts those living with a stigmatizing health condition. We propose to develop United Voices (UV), a community choir intervention to enhance psychosocial wellbeing among older PLWH, based on Community of Voices (COV; R01AG042526), a community choir intervention that significantly improved psychosocial outcomes in a cluster-randomized, waitlist controlled trial of older adults. The aims to this R21 are as follows. Aim 1: Develop United Voices, a community choir intervention to improve psychosocial wellbeing among older (≥50 years) PLWH by enhancing group pride and personal control. To achieve Aim 1, we will work with a community advisory council (CAC) of key stakeholders (e.g., older PLWH who have and/or are engaged in group singing) to adapt the COV intervention by drafting new protocols and procedures, modifying and refining the COV intervention protocols and procedures, and integrating the CAC's feedback into a final version of the UV manual and training procedures for the subsequent pilot trial in Aim 2. Aim 2: Conduct a pilot, randomized waitlist controlled trial of the United Voices intervention with two community sites to evaluate the acceptability and feasibility of implementation and assessment procedures and protocols, including randomization procedures. We will revise, integrate, and finalize intervention protocols and procedures to prepare for a subsequent full-scale trial. Findings from this R21 research will provide the foundational data needed for a subsequent R01 proposal to rigorously evaluate the first community choir intervention for addressing unmet needs among a growing and underserved population. Knowledge gained from the theory-based research proposed will inform future principles-driven intervention development research.