In this article, the authors first discuss the nature of peer support and some of the ways in which it has evolved over time, particularly in the UK. Under the umbrella of peer support they include activities such as befriending, peer counselling, conflict resolution or mediation and intervening in bullying situations. Secondly, they describe research studies of peer support and discuss their relevance to bystander behaviour. Thirdly, they draw some conclusions that relate to the wider context of the developing role of peer support in schools today. These include the benefits to peer supporters and the key processes of flexible monitoring and clear observation of the needs of the potential users.