It is unclear how consumer participation (CP) can be optimised to transform drug and alcohol treatment services and improve health outcomes. This paper presents the findings of a systematic review examining the types and benefits of activities, and the factors that facilitate CP in drug treatment services. Design A structured search of four databases was undertaken to identify peer reviewed primary research literature in English. Screened articles were appraised. A content analysis was applied to examine the types and outcomes of CP and the associated factors affecting the process. Sixteen articles were included for review. Findings A range of CP activities were identified, and benefits included increased consumer satisfaction, and improved health service delivery. Factors that facilitated the process of CP included positive attitudes of both consumers and providers and employment of people with a lived experience of drug use. However, the lack of consumer and organisational capacity, negative attitudes of providers and power imbalances between consumers and providers constrained CP efforts.