Gay, bisexual, and other men who have sex with men (MSM) are the population most severely affected by HIV in the U.S. and one of the only risk groups in the U.S. for which new infections continue to rise. MSM also experience a vastly disproportionate risk of mental health disorders, especially depression and anxiety. Numerous studies have shown that this mental health disparity arises from the early and ongoing stressors, known as minority stress, that MSM experience related to their sexual orientation. Despite the fact that minority stress is strongly related to anxiety and depression, and that minority stress and related mental health problems synergistically propel HIV risk behaviors, no existing HIV prevention intervention targets minority stress in order to reduce MSM's HIV risk behavior. This project aims to develop a theoretically-driven intervention that reduces the health-depleting effects of minority stress through targeting the basic psychosocial mechanisms linking minority stress to HIV risk behavior. These mechanisms include maladaptive emotion regulation, negative thinking styles, low self-efficacy, avoidance, and impulsivity, which are the very targets of an existing cognitive-behavioral, manualized intervention--the Unified Protocol for the Transdiagnostic Treatment of Emotional Disorders (UPTTED). The UPTTED changes these mechanisms using motivational interviewing, interoceptive and situational exposure, cognitive restructuring, mindfulness, and self-monitoring exercises, all grounded in cognitive-behavioral principles and developmental and affective neuroscience models of stress. The proposed study will adapt the UPTTED to support high-risk MSM's adaptive coping with minority stress, alleviate associated depression and anxiety, and reduce HIV risk behavior. The adapted UPTTED is expected to increase awareness of the unhealthy impact of minority stress; facilitate objective self-schemas in the face of minority stress; and strengthen one's skills and self-efficacy for managing minority stress and associated anxiety and depression to reduce risk for acquiring HIV. MSM who have experienced minority stress, mental health problems, and HIV risk behavior in the previous 3 months (n = 30) and community health experts (n = 30) will provide suggestions for adaptations to the existing intervention manual, including culturally relevant vignettes, examples, and exercises for adaptively responding to minority stress and managing HIV risk. The feasibility, acceptability, and preliminary efficacy of the adapted intervention will then be tested in a randomized waitlist controlled trial with MSM (n = 60) who report recent experiences with minority stress, depression and anxiety, and HIV risk behavior. The primary outcome will be HIV risk behavior. Secondary outcomes will be reductions in mediators including depression, anxiety, and the mechanisms of the conceptual model. This project innovatively seeks to test the preliminary efficacy of the first theoretically-driven intervention targeting the mental and sexual health consequences of minority stress and does so by targeting the underlying mechanisms that powerfully drive these simultaneous health threats.