This paper reviews definitions of, and commentary and research on peer support as a strategy in mental health service provision, summarizing areas of relevance to social work practice. It is a well-established in many countries, linked to the recovery movement. It provides peers to support people recovering from mental illness, seeing the personal and social journeys of people through mental illness as important aspects of improving their quality of life, accepting some social disability. It is connected with self-help, informal caregiver and advocacy movements and feminist ideas about treatment. Research reviews demonstrate that employing peers as supporters for people recovering from mental ill-health is feasible both in peer-led and in professional mental health provision. Outcomes are at least as good as professional help and peer support reduces use of expensive in-patient services. Positive features of the relationships between peers and patients brings benefits to both, building positive experiences in patients' lives and helping them manage disabilities.