Although peer-support programmes have a long history in UK prisons, only recently have they garnered attention from researchers wishing to explore their potential utility. Such programmes are built upon principles of mutual reciprocity, empathy, and emotional support. Growing research on these programmes suggests a number of ways in which they can help prisoners maintain positive mental health, and can help the providers of support as much as the recipients. Upholding a supportive role enables prisoners to develop meaning and purpose, garners a sense of control over their own problems, and in turn contributes to a heightened sense of well-being. This chapter discusses some of the emerging research relating to the potential impact of peer-support schemes in prisons. It provides a consolidated review of the potential application and trajectory of such schemes throughout the prison estate. A theoretical foundation on which this application might be based is offered. This chapter highlights some of the ways in which peer-support schemes can assist the prison system in addressing the issues related to mental health and well-being that most prisoners will face whilst serving time. Implications regarding this type of provision in terms of the efficacy of imprisonment and life beyond the gates are explored.