BackgroundIn Canada, rates of hospital admission from opioid overdose are higher for older adults (≥ 65) than younger adults, and opioid use disorder (OUD) is a growing concern. In response, Health Canada commissioned the Canadian Coalition of Seniors’ Mental Health to create guidelines for the prevention, screening, assessment, and treatment of OUD in older adults.MethodsA systematic review of English language literature from 2008–2018 regarding OUD in adults was conducted. Previously published guidelines were evaluated using AGREE II, and key guidelines updated using ADAPTE method, by drawing on current literature. Recommendations were created and assessed using the GRADE method.ResultsThirty-two recommendations were created. Prevention recommendations: it is key to prioritize non-pharmacological and non-opioid strategies to treat acute and chronic noncancer pain. Assessment recommendations: a comprehensive assessment is important to help discern contributions of other medical conditions. Treatment recommendations: buprenorphine is first line for both withdrawal management and maintenance therapy, while methadone, slow-release oral morphine, or naltrexone can be used as alternatives under certain circumstances; non-pharmacological treatments should be offered as an integrated part of care.ConclusionThese guidelines provide practical and timely clinical recommendations on the prevention, assessment, and treatment of OUD in older adults within the Canadian context.