The United States continues to experience a public health crisis related to substance use disorders (SUD) and an overdose epidemic that has only been exacerbated with the COVID-19 pandemic. An estimated 20.4 million individuals had a SUD in 2019, and preliminary studies show that this number likely increased as a result of the events of this past year. Medicaid is currently the largest payer of SUD services. Despite this coverage and the availability of evidence-based treatments, most individuals with SUD are currently not receiving treatment. Various states have sought to remedy the lack of access to treatment by requesting Section 1115 authorization to expand SUD services. In this webinar, we will discuss an analysis we conducted on these waivers. We will cover the clinical and legal framework about Medicaid coverage of SUD treatment, remaining gaps, and recommendations for improving practices.