Abstract Background Hepatitis C infection is a major public health concern globally. In Ireland, like other European countries, people who use drugs (PWUD) and prisoners carry a larger HCV disease burden than the general population. Recent advances in HCV management have made HCV elimination across Europe a realistic goal. Engaging these two marginalised and underserved populations remains a challenge. The aim of this review was to map key findings and identify gaps in the literature (published and unpublished) on HCV infection in Irish PWUD and prisoners. Methods A scoping review guided by the methodological framework set out by Levac and colleagues (based on previous work by Arksey & O’Malley). Results A total of 58 studies were identified and divided into the following categories; Epidemiology, Guidelines and Policy, Treatment Outcomes, HCV-related Health Issues and qualitative research reporting on Patients’ and Health Providers’ Experiences. This review identified significantly higher rates of HCV infection among Irish prisoners and PWUD than the general population. There are high levels of undiagnosed and untreated HCV infection in both groups. There is poor engagement by Irish PWUD with HCV services and barriers have been identified. Prison hepatology nurse services have a positive impact on treatment uptake and outcomes. Identified gaps in the literature include; lack of accurate epidemiological data on incident infection, untreated chronic HCV infection particularly in PWUD living outside Dublin and those not engaged with OST. Conclusion Ireland like other European countries has high levels of undiagnosed and untreated HCV infection. Collecting, synthesising and identifying gaps in the available literature is timely and will inform national HCV screening, treatment and prevention strategies.