This scoping review analyzed existing peer-reviewed literature on the use of medications for opioid use disorder (MOUD) within the criminal justice system. Researchers found four main categories of barriers and facilitators to the implementation of MOUD: institutional (characteristics, policies, regulations), programmatic (operations, practices, interventions), attitudinal (attitudes, knowledge, beliefs), and systemic (interactions between the criminal justice system and other systems). Thus, the extent to which MOUD is used within the criminal justice system is dependent on the interactions between these categories.