Johnson NJ, Choi S, Herrera CN, et al. - This study sought to compare changes in medication for opioid use disorder (MOUD) after the Affordable Care Act (ACA) to determine whether implementation was associated with increased MOUD for Black clients relative to White clients using a national sample of people seeking treatment for opioids (clients). Researchers distinguished 878,110 first episodes for clients with opioids as primary concern from SAMHDA's Treatment Episodes Data Set-Admissions (TEDS-A; 2007–2018). Descriptive and logistic regression analyses were conducted to calculate odds of MOUD for Black and White clients by Medicaid expansion status. It was shown that ACA was correlated with elevated use of MOUD among Black clients and reduction in treatment disparity between Black and White clients. Disparities in MOUD persist. Black clients with Medicaid in expansion states had the greatest reduction in disparities for criminal justice–referred Black clients.