This chapter provides an overview of the doctrine of the separation of powers under modern African constitutions. It begins by discussing the origins and nature of the doctrine, then explains the main models of separation of powers that have influenced developments in Africa. Next it looks at the approaches in Anglophone Africa and in the civilian jurisdictions in Africa, followed by a discussion of emerging new patterns of hybrid institutions which have the potential to enhance accountability. It is argued that the doctrine of separation of powers is an important instrument for limiting governmental arbitrariness. It is critical to dealing with broader issues such as the inclusion and protection of minorities, equitable resource allocation, and corruption. An effective system of separation of powers that limits the opportunity for abuse of powers provides a solid platform to deal with other challenges to constitutionalism, rule of law, and good governance in Africa.