PROJECT SUMMARY Implementation science (IS) plays an increasingly important role in the advancement of HIV research. Inherently multidisciplinary, IS recognizes that healthcare systems and communities often struggle to provide high quality services with limited resources. IS offers a growing number of evidence-based strategies for incorporating research investments in order to improve healthcare value and public health. Moving substantial investments in HIV research into practice in rapid, rigorous, and relevant ways is critical. The UCLA Rapid, Rigorous, Relevant Implementation Science Hub (UCLA 3R Hub) will provide IS expertise and, in coordination with the other Hubs, meet the demand for effective and efficient ways to translate HIV research into practice. The unique goal of the Hub is to provide leadership and support for rapid, rigorous, and relevant (3R) HIV- related implementation research emphasizing pragmatic study designs and methods that address health equity and produce sustainable solutions. We will reach this goal by accomplishing the following Specific Aims: 1) Build IS knowledge and capacity among EHE grantees by providing technical assistance (TA), coaching, and consultation to EHE grantees; 2) Collaborate with the Coordination, Consultation, and Data Management Center (CCDMC) and Regional Consultation Hubs (RCHs) by identifying resources and opportunities for advancing evidence-based interventions through the implementation pipeline; and 3) Build IS capacity in the HIV research community by providing and continuously enhancing, expanding, and refining a platform for learning in support of HIV-related implementation research, primarily through virtual IS Beachside Chats and IS Methods Workshops. EHE awardees assigned to the UCLA 3R Hub will have access to individualized TA, consultation, and coaching sessions; all-awardee meetings; IS Methods Workshops; IS Beachside Chats; and lectures and resources that will advance the application of IS concepts, theories, frameworks, and methods. Additionally, the UCLA 3R Hub will support the Coordinating Center’s efforts to advance shared measures and frameworks across the projects and via collective, synergistic activities. The UCLA 3R Hub team has a strong history of and urgent commitment to centering a health equity lens and engaging and mentoring diverse investigators, including racial/ethnic and sexual/gender minorities. Collectively, these activities and efforts will promote the research priorities of the EHE initiative, thereby enhancing HIV research and its impacts and applications in clinical care and public health more broadly.