Norms from the Periphery? African Agency in the Construction of International Peace and Security Rules examines the underestimation of African institutional agency in shaping international norms on sovereignty, intervention, accountability, and peace operations. Centering South Sudan without treating it as exceptional, the study situates the case within broader debates in constructivism, norm localization, and African agency in international relations. It develops the concept of southern norm entrepreneurship to explain how formal norms, institutional design, and struggles over authority interact in the production of international rules. Drawing on discourse analysis of AU normative instruments, including the Constitutive Act, Ezulwini Consensus, and Lomé Declaration; process tracing of African-led norm entrepreneurship episodes; interviews with AU Commission officials and African UN diplomats; and comparative analysis with ASEAN norm construction, the study advances three linked propositions. First, African regional organizations can shift norms from reactive positions to proactive proposals. Second, coalition-building and localization strategies are central to translating regional preferences into global norm debates. Third, the effectiveness of such efforts is constrained by structural inequalities within the international system. The analysis addresses the central question of how the AU has exercised norm entrepreneurship in areas such as non-indifference, the Ezulwini Consensus on the Responsibility to Protect, and positions on international criminal justice reform, and with what success in reshaping global normative frameworks. It shows that institutions, narratives, and policy processes function as political instruments rather than neutral containers. The study c