After participating in this activity, learners should be better able to:• Assess the treatment gap for patients with substance use disorders• Evaluate treatments and models of implementation for substance use disorders ABSTRACT: Substance use disorders (SUDs) account for substantial global morbidity, mortality, and financial and social burden, yet the majority of those suffering with SUDs in both low- and middle-income (LMICs) and high-income countries (HICs) never receive SUD treatment. Evidence-based SUD treatments are available, but access to treatment is severely limited. Stigma and legal discrimination against persons with SUDs continue to hinder public understanding of SUDs as treatable health conditions, and to impede global health efforts to improve treatment access and to reduce SUD prevalence and costs. Implementing SUD treatment in LMICs and HICs requires developing workforce capacity for treatment delivery. Capacity building is optimized when clinical expertise is partnered with regional community stakeholders and government in the context of a unified strategy to expand SUD treatment services. Workforce expansion for SUD treatment delivery harnesses community stakeholders to participate actively as family and peer supports, and as trained lay health workers. Longitudinal supervision of the workforce and appropriate incentives for service are required components of a sustainable, community-based model for SUD treatment. Implementation would benefit from research investigating the most effective and culturally adaptable models that can be delivered in diverse settings.