The Organisation of African Unity (OAU; French: Organisation de l'unité africaine, OUA) was an intergovernmental organization established on 25 May 1963 in Addis Ababa, Ethiopia, with 32 signatory governments. One of the main heads for OAU's establishment was Kwame Nkrumah of Ghana. It was disbanded on 9 July 2002 by its last chairman, South African President Thabo Mbeki, and replaced by the African Union (AU). Some of the key aims of the OAU were to encourage political and economic integration among member states, and to eradicate colonialism and neo-colonialism from the African continent.

The absence of an armed force like that of the United Nations left the organization with no means to enforce its decisions. It was also not willing to become involved in the internal affairs of member nations, prompting some critics to deride the OAU as a forum for rhetoric, not action. Recognizing this, the OAU in September 1999 issued the Declaration, calling for a new body to take its place. On 9 July 2002, this happened with the creation of the African Union. The African Union continues to this day to uphold many of the founding principles of the OAU.