PROJECT SUMMARY/ABSTRACT Discrimination is the most prominent stressor in Black individuals' everyday lives and can lead to a host of detrimental emotional health outcomes. Black adolescents and young adults report coping with racial discrimination by using alcohol or substances. Adolescent development unfolds amidst a complex system of relationships influenced by multiple levels (i.e., individual, interpersonal, contextual) of the social ecology. However, most research examining influences of racial discrimination on emotional health and substance use has focused on individual and interpersonal dimensions of the social ecological system separately. Examining risk and protective factors across multiple levels among Black youth who experience racial discrimination may identify novel leverage points for strengths-based interventions that jointly address experiences of discrimination and substance use to improve emotional health. The overall goal of this study is to examine Black youth's racial discrimination experiences and illuminate individual, interpersonal, and contextual risk and protective factors linking discrimination experiences with substance use and emotional health. We will leverage data and research infrastructure from an ongoing cluster-randomized trial of a racial, gender, and economic justice intervention for youth. In Aim 1, we will explore the interconnections of individual and interpersonal factors associated with racial discrimination, emotional health outcomes, and substance use behaviors over time. In Aim 2, we will conduct semi-structured interviews with Black youth to illuminate their experiences of racial discrimination and contextual factors influencing substance use behaviors. With committed mentors and strong institutional support, the PI will receive mentorship, didactic education, and research experience for her career development in theoretical frameworks, latent class analyses, advanced qualitative methods, and study management skills. This mentored research experience will prepare her for a K01 application to launch a career as an independent investigator focused on decreasing the psychological and substance-related impact of racial discrimination in minoritized groups through applied prevention research.