PROJECT SUMMARY/ABSTRACT Youth from resettled refugee families are at elevated risk of developing serious mental health challenges compared to their U.S. native peers. Studies have found that refugee youth living in high income countries have high prevalence of trauma-associated mental disorders like PTSD, (19% to 54%) and depression (3% to 30%). Additionally, youth belonging to these vulnerable communities have high rates of substance use, school dropout, incarcerations, violence including gang-related homicides, with suicides emerging as a serious public health threats. The purpose of this K01 is to provide the candidate with formal training and mentoring in: (1) systematically adapting and implementing community-based interventions; (2) collection, management, and analysis of qualitative and mixed methods data; and (3) advanced implementation science research, including the application of theories and frameworks, methods for identifying and prioritizing implementation determinants, and systematic approaches to developing and testing implementation strategies. This training will prepare the candidate for independent research conducting multidisciplinary research that develops and tests community- based interventions aimed at addressing the myriad of mental health challenges among youth in resettled refugee communities. Accordingly, the candidate will conduct a type 1hybrid effectiveness-implementation trial to test a combination intervention designed to improve intergenerational trauma-related mental health symptoms among second generation refugee children (SGRC). Guided by Social Action and Family Systems theories, and applying them to the ITT framework, the proposed combination intervention consists of: family strengthening (FS) model delivered through multiple family groups (MFG) + peer mentoring program called TeenAge Health Consultants (TAHC) adapted for delivery in virtual environment (Virtual TAHC). The intervention will have the following specific aims: (1) systematically adapt an evidence-based family strengthening (FS) model delivered through multiple family groups (MFG) combined with a peer mentoring program (Virtual TAHC) (Goal 1); (2) assess preliminary short- and long-term impact of the combination intervention (MFG + Virtual TAHC) on behavioral emotional disorders (aggressive behavior, antisocial behaviors, anxiety, depression, and PTSD) related to intergenerational trauma among SGRC in the trial (Goal 2); and (3) utilizing mixed methods and applying the Exploration, Preparation, Implementation, Sustainment (EPIS) framework, examine implementation strategies, facilitators, and barriers of the RRF4H intervention (Goal 3). Given the transdiagnostic application of the intervention, this study is significant because it has potential to advance our understanding on how to mitigate the intergenerational impact of war trauma among children who have not directly experienced war trauma.