SUMMARY ABSTRACT Both substance use disorders (SUDs) and HIV are subject to stigma, namely, the process by which an attribute is deemed deeply discrediting and prone to prejudice and discrimination. Stigma toward SUDs and HIV arises from multiple sources, including policies or individuals who carry out policies (“structural stigma”) and health professionals (“provider-based stigma”). Stigma from health professionals experienced or anticipated by people with SUDs can create barriers to accessing high-quality health services. For people with SUDs who need HIV prevention or care, the added stigma of HIV may compound substance use-related stigma to enhance social barriers to healthcare. However, few studies have examined the role of substance use stigma in HIV healthcare contexts, or how to intervene on substance use stigma in this doubly-sensitive area of healthcare. Extant studies on substance use stigma in other healthcare contexts found that educational interventions incorporating critical reflection techniques and opportunities for contact with people who use drugs may significantly reduce provider- based stigma. An even greater limitation is that provider-based stigma intervention studies fall short of practical application: they largely focus on attitudinal outcomes among professionals, but do not measure the effects of policies or how stigma interventions affect healthcare utilization or patient health outcomes. For HIV prevention and care contexts to improve healthcare quality and outcomes among people with SUDs, interventions are needed to reduce provider-based and structural stigma perennially attached to substance use. Our goal is to adapt and refine a multi-level stigma intervention that leverages professional education and organizational policy to address structural drivers of stigma and the stigmatizing professional attitudes and behaviors that determine patient care and health. To achieve this goal, this planning project will work with federally qualified health centers (FQHCs) to address three Specific Aims: 1) Create a substance use curriculum for HIV prevention and care contexts that pilot testing demonstrates significantly improves knowledge, attitudes, and planned actions related to professional stigma towards people who use drugs; 2) Use qualitative interviews with FQHC administrators and personnel to identify organizational policies that improve conditions of professional decision-making and may enhance the effects of professional education on stigma reduction; and 3) Develop, optimize, and finalize a trial design and protocol that is intended to test how the multi-level SUD stigma intervention influences intermediate outcomes related to SUDs and professional and patient stigma, as well as principal HIV outcomes related to prevention and care. This project will use community-engaged research methods with FQHCs to develop a multi-level stigma intervention and trial protocol that seeks to test whether combining educational and or...