The goal of this study is to characterize the role of social, behavioral, and economic stigmas as barriers to optimizing HIV and mental health outcomes among men at high risk of HIV across the US. Social, behavioral, and economic stigmas (SBE stigmas) include enacted, perceived, and anticipated stigmas related to specific attributes including socioeconomic status, demographic characteristics, occupation, and health-related behaviors. This proposal was developed in response to the need to better characterize the role of stigma and the mechanisms by which they act as a barrier to ending the HIV epidemic in the US. A high prevalence of mental, physical, and sexual health problems has consistently been documented among men at higher risk of HIV, including sexually transmitted infections, depression and anxiety, and substance use. While social, behavioral, and economic stigmas are understood to affect sexual and mental health outcomes, there is limited consensus on both the optimal measurement of SBE stigmas and describing the mechanisms by which SBE stigmas drive differences in sexual and mental health outcomes, including those modifiable through health and behavioral interventions. We will leverage the American Men’s Internet Survey (AMIS) in the US to collect data on trends in SBE stigmas and health outcomes in five cross-sectional online surveys of high-risk men (n=5,000 in Years 1-5) accompanied by testing of self-collected biospecimens from 500 AMIS participants per survey (n=1,500 total in Years 1, 3, 5). With the goal of informing evidence-based interventions towards mitigating the health harms of SBE stigmas, we propose a mixed-methods, transformative study designed to meet the proposed aims: Aim 1: Optimize metrics of SBE stigmas experienced by men at higher risk of HIV sampled online in the US. Aim 2: Qualitatively explore perspectives among men at higher risk of HIV for how SBE stigmas shape engagement in HIV prevention and treatment and mental health services. Aim 3a: Characterize cross-sectional relationships between SBE stigmas and engagement in HIV prevention/treatment and other healthcare services among national samples of men at higher risk of HIV in the US. Aim 3b. Determine demographic, geographic, and temporal heterogeneities in the burden of SBE stigmas and associations with sexual health, mental health and resilience, and engagement in HIV prevention and treatment in follow-up cross-sectional nationwide surveys of men at higher risk of HIV. The proposed aims address a well-known gap in the measurement of SBE stigmas, characterizing health outcomes of SBE stigmas, describing the mechanisms driving health and wellbeing, and informing interventions to improve overall health given the focus on multiple health outcomes that continue to cause significant morbidity and mortality across the US. The team assembled has the requisite experience and expertise to implement these ambitious aims as a means of optimizing the health and ...