This Element addresses questions of division of labor and concentration of authority among intergovernmental organizations by examining multilevel governance in the Global South. It focuses on the policy domains of peace and security and human rights in Africa and Latin America and the Caribbean (LAC), and its central finding is that the extent of governance regionalization varies across regions and issue areas. In the domain of peace and security, governance is most regionalized in Africa. In the domain of human rights protection, governance is most regionalized in the LAC region. Given the phenomenon of regional specialization, the Element makes the case for the greater explanatory power of regional drivers of regional institutional development. This Element is also available as Open Access on Cambridge Core.