A vision of cleantech has been implemented on an international scale with financial assistance, new organizations and programmes. Given the wider contexts of political and commercial promotion, this article investigates management and governance of eight cleantech networks operating in different regions in Sweden. The aim of this article is to explore how an integrated approach based on network theories of economic sociology and a regional development perspective can contribute to the study of network intermediaries. What roles do intermediaries play in triple-helix networks? A suggested answer to this question is a typology of three intermediaries: a brokerage function for business agreements, a facilitation function whereby actors facilitate various processes and co-ordinate arrangements and a legitimizing function involving activities conducted in the political and wider societal realms. The legitimiser role of regional cleantech networks has important feedback effects on the wider discourses of environmental development, of which cleantech is a particular and influential vision.