Required for peace and security, economic governance, sustainable development and humanitarian support, International Organisations (IOs) are central to the structure of global governance. Introducing the importance of governance in IOs, this Handbook addresses the collective challenges and synthesizes the expertise of global or regional representativeness for international cooperation.Addressing four key themes the contributors explore approaches to understanding governance in IOs; who governs IOs; the roles of states; organizational culture, leadership and gender; and the influence of civil society. Chapters further evaluate historical representations of successful and unsuccessful governance, including effective governance; institutional and individual accountability; and the need for reform. The Handbook then concludes with key reflections on the frequently asked question: have international organisations had their day?With contributions by leading academics and practitioners in the field, this Handbook elucidates the evolution of governance in IOs. It will be of great value to students and researchers in international relations, global governance, and gender and governance.