St. John's Community Health's South Los Angeles Young Adult Prevention and Empowerment Project ("SLAY") is a queer young adult-driven communitywide effort to provide substance misuse and HIV prevention services for underserved, low-income queer young adults (QYA) of color (ages 18-29) in South Los Angeles, California. (Los Angeles County is one of the localities hardest hit by the HIV epidemic in the U.S.) The carefully planned individual-, group-, and community-level strategies of SLAY, rooted in SPF processes and lessons learned form previous efforts, aim to subvert the persistent trend in South LA where QYA are disproportionately impacted by high rates of HIV, viral hepatitis (VH) and other sexually transmitted infections (STI); substance misuse; housing insecurity; poverty; homo-/transphobia and racism; and the justice system. The goals of SLAY are to: (1) Engage South LA QYA with HIV/substance misuse prevention and mental health promotion messaging via in-person, street-based, virtual, and social media outreach; and (2) Prevent substance misuse, address substance use and mental health disorders, reduce HIV/STI/VH risk, and ensure connection to needed services for QYA in South LA. All of the population of focus are people of color (80% Latinx, 20% Black); 25% transgender/gender nonconforming; 30% are unstably housed or unhoused; 15% are immigrants best-served in Spanish; 10% are justice-involved; and 100% are low-income (under 200% FPL). Approximately 80% served will be QYA of any gender who have sex with males; the remaining will be at-risk QYA of any gender/sexual orientation. A total of 350 unduplicated QYA will be served (50 in Year 1 and 75 in each subsequent year) through this grant. Objectives include: (1) training 40 QYA as Peer Prevention Leaders; (2) developing and launching online and social media campaigns to recruit QYA to participate in SLAY interventions and to provide HIV/substance misuse prevention and mental health promotion education messages; (3) engaging 2,400 QYA with SLAY education messages; (4) educating 250 providers and support staff on the importance of HIV/VH screening and on QYA cultural competency; (5) providing HIV and VH testing and referrals to treatment and PrEP for 700 QYA; (6) providing SBIRT and screening for co-occurring mental health problems and other psychosocial issues for 475 QYA; (7) enrolling 420 QYA in our SLAY-group intervention based on the Mpowerment EBP; (8) providing navigation services to ensure that QYA have the health and social resources they need; and (9) increasing sense of hope, functioning, self-efficacy, and social connection among QYA in South LA.