PROJECT SUMMARY The use of virtual sociosexual networking venues (e.g., mobile apps and websites) to find intimate partners is near ubiquitous among young sexual minority (SM) men. However, little attention has been paid to the unique discriminatory phenomena that occur in online spaces, and how these experiences impact the mental health of young sexual minority men of color (YSMMoC). One such phenomenon that has been understudied is Racialized Sexual Discrimination (RSD), defined as the sexualized discriminatory treatment that YSMMoC encounter online when looking for intimate partners. RSD, also referred to as `sexual racism,' is widespread within these spaces, and may be a part of the broader constellation of race-based micro-aggressions that YSMMoC encounter in their daily lives. Thus, YSMMoC who regularly use virtual spaces to meet intimate partners may be at elevated risk for poor psychosocial outcomes. To date, the few studies that have quantitatively investigated RSD have not used validated scales that capture the multiple aspects of RSD that are unique to online settings. To address these gaps, the PI launched an exploratory mixed-methods study to develop and test a multi-dimensional scale of RSD with young Black SM men and examine the associations between RSD and psychological well-being. Exploratory factor analyses of the initial scale revealed an 8-factor structure. The scale was found to be reliable and psychometrically sound, and four factors of RSD were negatively associated with depressive symptoms and feelings of self-worth. Additional research is needed, however, to examine the psychometric properties of the RSD scale for other YSMMoC and the predictive validity of RSD to a more comprehensive set of indicators of psychological well-being. Thus, the goal of the current study is to further advance the development and validation of a novel, multidimensional scale of RSD in an online sample of N=1,500 YSMMoC. The specific aims are to: (1) perform a Confirmatory Factor Analysis (CFA) and reliability analysis with N=500 Black men using structural equation models; (2) test for measurement invariance across racial/ethnic groups by performing additional CFAs and reliability analyses among a sample of N=500 Latino and N=500 Asian men; and (3) examine the relationship between RSD factors and four indicators of psychological well-being, e.g., depression, loneliness, self-worth and life satisfaction. Our examination of RSD is guided by Minority Stress Theory and Intersectionality, two conceptual frameworks prioritized in the Institute of Medicine's seminal report on LGBT health. Addressing experiences of discrimination among YSMMoC is a high-priority area for NIH, and psychological functioning among this population remains a significant public health concern. Thus, developing a robust and comprehensive measure of RSD will significantly advance health equity research aimed at mitigating the negative effects of discrimination on the mental heal...