The Friends Research Institute Hub is conducting a comparative effectiveness trial of extended-release naltrexone (XR-NTX) versus a new extended-release formulation of buprenorphine (Brixadi, XR-B) to treat OUD among justice-involved individuals in ten Maryland county jails. In this trial, participants are randomly assigned to receive either XR-NTX or XR-B prior to release from jail, followed by six monthly injections while in the community. The goal of the study is to evaluate the effectiveness of the two medications, measure medication adherence, and gather data to inform a broader scale-up of MOUD in jails and in the community.