BACKGROUND: Substance use increasingly contributes to early morbidity and mortality, which necessitates greater preparation of the healthcare workforce to mitigate its harm. The purpose of this systematic scoping review is to: 1) review published curricula on harm reduction for substance use implemented by undergraduate (UME) and graduate medical education (GME) in the United States and Canada, 2) develop a framework to describe a comprehensive approach to harm reduction medical education, and 3) propose additional content topics for future consideration. METHODS: PubMed, Scopus, ERIC: Education Resources Information Center (Ovid), and MedEdPORTAL were searched. Studies included any English language curricula about harm reduction within UME or GME in the United States or Canada from 1993 until Nov 22, 2021. Two authors independently reviewed and screened records for data extraction. Data were analyzed on trainee population, curricula objectives, format, content, and evaluation. RESULTS: Twenty-three articles describing 19 distinct educational programs across the United States were included in the final sample, most of which created their own curricula (n = 17). Data on educational content were categorized by content and approach. Most programs (85%) focused on introductory substance use knowledge and skills without an understanding of harm reduction principles. Based on our synthesis of the educational content in these curricula, we iteratively developed a Harm Reduction Educational Spectrum (HRES) framework to describe curricula and identified 17 discrete content topics grouped into 6 themes based on their reliance on harm reduction principles. CONCLUSIONS: Harm reduction is under-represented in published medical curricula. Because the drug supply market changes rapidly, the content of medical curricula may be quickly outmoded thus curricula that include foundational knowledge of harm reduction principles may be more enduring. Students should be grounded in harm reduction principles to develop the advanced skills necessary to reduce the physical harm associated with drugs while still simultaneously recognizing the possibility of patients ongoing substance use. We present the Harm Reduction Educational Spectrum as a new framework to guide future healthcare workforce development and to ultimately provide the highest-quality care for patients who use drugs.