This briefing paper analyses the Intergovernmental Authority on Development (IGAD), the principal regional organisation in East Africa. It examines IGAD’s mandate, institutional development, and challenges, with a focus on peace and security, governance, economic cooperation, and environmental management. The paper situates IGAD within the broader architecture of African and global multilateralism, highlighting both its contributions—such as mediation in Sudan and Somalia—and structural weaknesses including overlapping memberships, weak governance, and limited institutional capacity.