A narrative systematic review was undertaken of the literature concerning the health of people on probation or parole (community supervision). In this paper, we provide an up-to-date summary of what is known about substance misuse in this context. This includes estimates of the prevalence and complexity of substance misuse in those under community supervision, and studies of the effectiveness of approaches to treating substance misuse and engaging and retaining this population in treatment. A total of 5125 papers were identified in the initial electronic searches, and after careful double-blind review only 31 papers related to this topic met our criteria. In addition, a further 15 background papers were identified which are reported. We conclude that internationally there is a high prevalence and complexity of substance misuse amongst people under community supervision. Despite clear benefits to individuals and the wider society through improved health, and reduced re-offending; it is still difficult to identify the most effective ways of improving health outcomes for this group in relation to substance misuse from the research literature. Further research and investment is needed to support evidence-based commissioning by providing a detailed and up-to-date profile of needs and the most effective ways of addressing them, and sufficient funds to ensure that appropriate treatment is available and its impact can be continually measured. Without this, it will be impossible to truly establish effective referral and treatment pathways providing continuity of care for individuals as they progress through, and exit, the criminal justice pathway.