CAPACITY SUPPORTING CORE ABSTRACT The Innovative Network on the Science and Practice of Implementation, Research, and Engagement (INSPIRE) Capacity Supporting Core seeks to leverage the strengths and assets within the Prevention and Treatment through a Comprehensive Care Continuum for HIV-affected adolescents in resource-constrained settings implementation science network (PATC3H-IN) to adapt, scale-up and sustain evidence-based HIV research for adolescents and young adults in low- and middle-income countries. We will offer a 5-day co- created D&I course focused on key concepts such as adaptation, scale-up, and sustainability for eight early career researchers and implementers or practitioners as part of the annual PATC3H-IN meeting held with participating Clinical Research Centers. We will also organize a 3-day designathon (similar to hackathons), where participants prepare with end-users, intensively collaborate (often 48-72 hours), and then implement solutions in local areas. Scholars and implementers will share lessons learned, lead the design, and launch of emerging research pilots funded by the PATC3H-IN network as well as competitive seed grants (n=10) sponsored by the INSPIRE Capacity Supporting Core to promote the adaptation, scale-up, or sustainability of evidence-based HIV research for AYA. As part of our synergistic interactions, we will partner with the INSPIRE Advanced Methods and Modeling Core (AMMC) to lead the emerging research pilots' program with PATC3H- IN Coordinating Operating Center on emerging methods (i.e., preferences, agent-based modeling, costing) for adapting, scaling-up and sustaining evidence-based research. To enhance AYA engagement in community- engaged research and dissemination with other non-academic partners, we will partner with the INSPIRE Community Engagement and Dissemination Core to conduct the annual team-based designathons focused on adapting, scaling up, or sustaining evidence-based HIV research for AYA. Our overall goals are to foster research and capacity support to accelerate the adaptation, scale-up, and sustainability of evidence-based interventions to end the AYA HIV epidemic. Our specific aims are: 1) To co-create and implement an INSPIRE dissemination and implementation (D&I) science course, a year-long learning program, and grant-writing retreat for trainees in LMICs; 2) To implement INSPIRE team-based designathons to nurture academic and non-academic partnerships and engagement; and 3) To lead rapid and iterative evaluation of INSPIRE capacity supporting program, track research, and career development as well as translational impact. The INSPIRE Capacity Supporting Core will lay the foundation for a strength-based, collaborative training and engagement approach that moves from a deficit mindset of what society is doing poorly (i.e., no capacity to begin with) to one that is positive about what society can achieve to adapt, scale up, and sustain evidence- based HIV interventions for adolescents and young adults in low- to-middle income countries.