As the largest payer of substance use disorder services in the United States, Medicaid plays a central role in state efforts to address the opioid epidemic. In addition to increasing access to addiction treatment services through the expansion of Medicaid under the Affordable Care Act (ACA), states are expanding Medicaid addiction treatment services, increasing provider reimbursements, restricting opioid prescribing, and implementing delivery system reforms to improve the quality of treatment services. While many states have been tracking progress and challenges in these efforts, uniqueness of state systems can make it difficult to compare or benchmark across states. This brief draws on analyses provided by the Medicaid Outcomes Distributed Research Network (MODRN), a collaborative effort to analyze data across multiple states to facilitate learning among Medicaid agencies. It profiles the opioid epidemic among the Medicaid population in six states participating in MODRN that also have been hard hit by the opioid epidemic: Kentucky, Maryland, Ohio, Pennsylvania, Virginia, and West Virginia. The brief also draws on interviews with officials from the state Medicaid and other health agencies.