To what extent can international institutions learn? What factors determine whether such institutions develop capacities for self-awareness and endogenous institutional change? This project investigates these questions in the context of the European Union (EU). Specifically, it examines the dramatic expansion in security missions led by the EU since 2003, a capacity that many observers doubted was even possible for the EU. To explain this change in institutional behaviour, the project intends to develop a theory of institutional learning to analyze the EUs instigation and implementation of 16 security operations in various regions under the auspices of the European Security and Defence Policy (ESDP). In addition, with these missions the EU has shown a growing capacity to innovate in security affairs, using a unique civilian crisis management (CCM) capacity linked to security sector reform and other EU policy tools, including the ESDP, the Common Foreign and Security Policy (CFSP), and the European Neighbourhood Policy (ENP). These changes demand further examination in light of not only the growing ambitions of the EU itself but also in terms of the increasing demands for security assistance placed on a variety of IOs, such as the UN, NATO, and the OSCE. The initial phase of the project will focus on four key ESDP operations as detailed case studies Macedonia, the Palestinian Authority, the Democratic Republic of the Congo, and Bosnia-Hercegovina to explain this innovation. Following the investigation of these representative cases, the later stages of the project will examine more recent EU security operations in hopes of developing a general theory of EU institutional learning in the area of foreign/security/defence policy. The project also hopes to generalize beyond this theory to other EU policy domains and, potentially, other IOs at the regional and global levels. In doing so the findings could have major implications for global governance.