Against the backdrop of a decade of protracted high-intensity, often transnational conflicts and a decrease in human development across sub-Saharan Africa in the 1990s, Africa continues apace with the process of transformation of the norms and institutions governing the continent. This has led to new practices on the mutually constituted challenges of peace, security and development. It also alters the nature of bilateral relations within Africa and its global interactions. The transformation of the Organization of African Unity (OAU) into the African Union (AU), launched in Durban, South Africa, in July 2002, expanded the sources of authority of the organization and created a fully-fledged AU Commission (AUC) that is substantially more powerful than the OAU’s Secretariat had been. In addition to the Assembly of Heads of State and Government (AHSG), the Executive Council and the Permanent Representatives Committee, the AU has created judicial, democratic and civil society pillars (the Court of Justice, the Pan-African Parliament and the Economic, Social and Cultural Council). The most important area of change, however, regards the establishment of a new peace and security architecture for Africa (APSA), which in conjunction with the recent African Governance Architecture (AGA) have focused the organization squarely on the prevention, management and resolution of violent conﬂict. This chapter provides an overview of this new architecture and its implementation and highlights some of its most pressing institutional, ﬁnancial and political challenges.