We are constantly talking about networks. Banks use their networks to offer global services to customers; airlines fly passengers all over the world via their networks of partners; news agencies use media networks to keep us informed every minute of the day; and terrorist networks threaten citizens around the world. The importance of networks extends to the development sector: they organise civil society to advocate for and implement change; they link the local with the global, the private with the public; and they provide spaces for the creation, sharing and dissemination of knowledge. In a way, networks seem to make anything and everything happen. But we have yet to understand what they are and what they can and cannot do. In the development literature, a huge variety of policy and social network concepts and applications exists. This paper attempts to set out a framework to help clarify what research policy networks do.