The Canadian Research Initiative in Substance Misuse (CRISM) has developed this practice guideline based on current and rigorously reviewed evidence to provide Canadian healthcare professionals with an educational tool and clinical practice recommendations for the treatment of OUD. This guideline is also intended to inform further discussions and collaborations in federal and provincial/territorial policy and program planning. Accordingly, current province-specific training requirements, regulations for prescribing, and dosing schedules for methadone and buprenorphine/naloxone have been provided as appendices.