Psychological distress among sexual minority populations remains a persistent public health concern in the United States, with lesbian, gay, and bisexual (LGB) adults experiencing disproportionately higher mental health burdens compared to heterosexual populations. This study presents a population-based epidemiological assessment of psychological distress and its sociodemographic and behavioral determinants among LGB adults in the United States between 2013 and 2018. Drawing upon national surveillance systems and health interview datasets, the study synthesizes evidence on prevalence patterns, behavioral risk factors, and structural determinants influencing mental health outcomes. The conceptual foundation is informed by stress process theory and minority stress frameworks, which explain how stigma, discrimination, and socioeconomic disadvantage contribute to elevated psychological distress in sexual minority groups (Meyer, 2003). Evidence from national surveys indicates persistent disparities in mental health outcomes, with LGB individuals exhibiting significantly higher levels of serious psychological distress compared to heterosexual counterparts (Gonzales et al., 2016; Blackwell et al., 2014). Behavioral factors such as substance use, smoking, and physical inactivity further compound mental health risks, while socioeconomic conditions such as income instability and lack of insurance intensify vulnerability. The study highlights the importance of integrated public health surveillance systems for monitoring disparities and informs targeted interventions aligned with Healthy People 2020 mental health objectives. Findings underscore the need for structural and behavioral interventions to reduce inequities in psychological distress among LGB populations in the United States.