SummaryPeer worker roles are being introduced in mental health services in the UK and internationally, to support individuals in their recovery. There is substantial qualitative evidence that demonstrates benefits at an individual level and some evidence of impact on service use and costs, although there are currently few high-quality randomised controlled trials supporting these findings, especially from the UK. A growing body of research indicates that careful consideration of organisational issues regarding the introduction of peer worker roles – the distinctiveness and shared expectations of the role, strategic alignment, organisational support – might maximise their impact. Properly supported and valued peer workers are an important resource to the multidisciplinary team, offering experiential knowledge and the ability to engage patients in their treatment through building relationships of trust based on shared lived experience.LEARNING OBJECTIVESAppreciate the origins of the peer worker role and how the role has been introduced into mental health services to date.Understand the evidence for the benefits of peer worker roles, for patients, peer workers and mental health service delivery.Demonstrate awareness of the organisational and team-level barriers to and facilitators of introducing peer workers into, or alongside, existing multidisciplinary mental health teams.