Peer support is based on the belief that people who have faced, endured, and overcome adversity can offer useful support, encouragement, hope, and perhaps mentorship to others facing similar situations. While this belief is well accepted for many conditions, such as addiction, trauma, or cancer, stigma and stereotypes about mental illness have impeded attempts on the part of people in recovery to offer such supports within the mental health system. Beginning in the early 1990s with programs that deployed people with mental illness to provide conventional services such as case management, opportunities for the provision and receipt of peer support within the mental health system have proliferated rapidly across the country as part of the emerging recovery movement. This article defines peer support as a form of mental health care and reviews data from 4 randomized controlled trials, which demonstrated few differences between the outcomes of conventional care when provided by peers versus non-peers. We then consider what, if any, unique contributions can be made by virtue of a person’s history of serious mental illness and recovery and review beginning efforts to identify and evaluate these potential valued-added components of care. We conclude by suggesting that peer support is still early in its development as a form of mental health service provision and encourage further exploration and evaluation of this promising, if yet unproven, practice.