PROJECT SUMMARY/ABSTRACT Suicide and suicide thoughts and behaviors (STBs) increased at alarming rates among Black youth over the last decade, faster than any other racial/ethnic group. Suicide is now the third leading cause for Black youth. As highlighted in RFA-MH-22-141, there is an urgent need to identify risk and protective factors for suicide and STBs among Black youth, which in turn can inform the development of prevention and intervention approaches. The proposed research directly addresses that need by examining theoretically- and culturally informed risk and protective factors for STBs in an especially vulnerable group: justice-involved Black youth (JIBY). Rates of suicide and STBs are particularly high among JIBY, exceeding rates among the general population. Studies examining JIBY experiences in family, school, community, and juvenile justice are rare, in part because justice- involved are a hard-to-reach population; youth in custody are poorly represented in school-administered national youth survey data intended to collect data for the general population. Further, prior research on STBs among Black youth has been driven largely by Eurocentric or race-neutral perspectives and an emphasis on single risk factors rather than a concentration of risk factors that JIBY often experience.We propose to leverage 11-years of state-wide, longitudinal data from the Florida Juvenile Justice Department (total N > 346,000 Black youths) to (1) determine group trends and within-person changes in STBs and (2) identify how risk and protective factors in different life domains intersect to increase and decrease the risk of STBs among JIBY. We will disaggregate trends by age, gender, mental health, substance misuse, family environment, and other individual and environmental factors. We also will identify within-person trends in STBs over time. Working from a concentrated disadvantage framework, we will use higher-order interaction selection and classification to examine how risk and protective factors across multiple domains influence risk of STBs. Further, we will (3) supplement these quantitative analyses with qualitative interviews that center JIBY perspectives on risk and protective factors, barriers they face in sharing and communicating STBs, and experiences with mental health services. Overall, this project will provide novel insights into how suicide risk unfolds in the life context of JIBY and identify the intersection of stressors in the family, school, neighborhood, and justice domains that influence STBs among JIBY. Such insights will directly inform the development of culturally responsive suicide screening, prevention, and intervention approaches for JIBY.