This article examines the role of non‐governmental organizations (NGOs) in environmental governance systems with a particular emphasis on non‐state market‐driven governance in the green building industry. Based on an extensive literature review, a conceptual framework of the function of NGOs in environmental governance is developed, focusing on five core aspects – role, power, accountability, legitimacy and acceptance – that define the position of NGOs in a governance system in relation to other stakeholders. The World Green Building Council's (WGBC's) global environmental governance movement has been identified as a dynamic market‐driven governance system. Thus, the paper explores the role of regional green building councils (RGBCs) listed in the WGBC's directory within this newly deployed governance system. The results confirm the proposition that RGBCs grow in their governance and third‐party role as they progress through the development stages proposed by the WGBC. Copyright © 2014 John Wiley & Sons, Ltd and ERP Environment