Despite the long-recognized interlinkages between global energy consumption and climate change, there has historically been only limited policy interaction, let alone integration, between the two fields. This compartmentalization is mirrored in scholarship, where much research has focused on the fragmentation of, respectively, global energy and global climate governance, but only little has been said about how these fields might be integrated. Our analysis of the International Energy Agency's (IEA) changing activities in recent years shows that governance integration - both within global energy governance and between global energy and climate governance - is now happening. The IEA has broadened its portfolio to embrace the full spectrum of energy issues, including renewable energy and climate change; it has built and is expanding key partnerships with both the UN climate convention and the International Renewable Energy Agency (IRENA); and it has become an authoritative advocate for the inter-related goals of a low-carbon transition and climate change mitigation. We show that these developments are not the result of a top-down plan, but have rather emerged through the Agency's various efforts to pursue its energy-centric mandate in a fast-changing global policy environment. (C) 2015 Elsevier Ltd. All rights reserved.