This proposed randomized control trial will test the pharmacotherapy adherence (number of monthly injections received) of extended-release buprenorphine (XR-B) versus extended-release naltrexone (XR-NTX) among adults with opioid use disorder (OUD) who are nearing release from county jails in Maryland. The results of this trial will have substantial public health implications as most individuals with OUD do not receive treatment while incarcerated, raising the likelihood of relapse, overdose, and-reincarceration.