MOUD is prevalent among individuals who are incarcerated, yet medications for opioid use disorder (MOUD) are not widely available in US jails and prisons. Negative staff attitudes across the criminal legal system may prevent MOUD from being provided. We sought to determine if staff attitudes are associated with the provision of MOUD in prisons or jails. 227 staff members of 43 jails and partnering community-based treatment providers answered questions on the effectiveness and acceptability of methadone, buprenorphine, and naltrexone. Sites whose staff had negative attitudes towards methadone and positive attitudes towards naltrexone were associated with fewer people being screened, diagnosed, referred, provided MOUD, and referred after release. Sites with overall positive attitudes towards all MOUD were associated with more people being screened, diagnosed, and referred to treatment.