Can A Youth Leadership and Mindfulness Program Support Well-being in Adolescence? - This study tests the effectiveness of a youth leadership program with a mindfulness component in improving the mental, emotional, and behavioral (MEB) health of youth and their leadership skills. Specifically, we examine whether the Leadership, Engagement, and youth Action Program with Mindfulness (LEAP) is a feasible and effective intervention to foster leadership among youth, and can consequently improve youth MEB health and well-being. The 7-week LEAP intervention was designed in partnership with youth to develop leadership skills and foster peer relations, and to improve their well-being. LEAP integrates training in mindfulness throughout the intervention to support youth in their leadership work. Our prior research has demonstrated that increasing leadership skills can improve MEB health for youth across different population groups. Our long-term goal is to evaluate whether LEAP can effectively improve leadership skills and the MEB health and well-being of all youth, and whether there are variations in treatment response across different population groups. In UG3 Phase 1, we will in Aim 1.1 develop collaborative partnerships with partner school sites, in Aim 1.2 modify the design with partner input and co-create an engagement plan for recruitment and retention, and in Aim 1.3 conduct a pilot study (N=40) to test protocols and refine the methodology with partner feedback. In UH3 Phase 2 we will in Aim 2.1 conduct a two-site 2-arm randomized controlled trial to test the acceptability and effectiveness of LEAP as a mechanism for improving youth MEB health and leadership skills (N=504) at the 3-month primary endpoint. Youth will be randomly assigned to participate in LEAP or in a comparison college and career readiness program of equal duration. In Aim 2.2 we will test whether the potential effect of LEAP varies as a function of student demographic factors. In Aim 2.3 we will test the effectiveness of LEAP on youth MEB health at the exploratory 6- and 9-month endpoints. In Aim 2.4 we will identify potential pathways influencing the link between LEAP and youth well-being and leadership skills. Finally, in Aim 2.5 we will evaluate the cost-effectiveness of the LEAP intervention compared with the college and career readiness program to estimate the potential incremental effects of the intervention. The proposed project is expected to provide research to improve youth MEB health by using a leadership and mindfulness intervention that, if effective, can be brought to scale.