Enlargement of the African Union

When the African Union (AU) was founded in 2002, it represented almost the entire African continent. As the successor to the Organisation of African Unity (OAU), founded in 1963, its membership was inherited from that body. Currently, the AU has 55 member states. Growth in the OAU typically came from post-colonial independence; as decolonization ended, the borders of the OAU had overlapped almost all of Africa.
Membership.
 of the Constitutive Act of the African Union (ratified July 11, 2000), states:
The following two articles discuss the suspension and cessation of membership:
and
The former of these two clauses has been used to suspend the participation of states in the AU a number of times. The only state to leave the OAU was Morocco, which withdrew in 1984, following the admission of the Sahrawi Arab Democratic Republic in 1982. It joined the AU in 2017.
Current members.
Between 1984 and 2017, Morocco was the only UN Member state in Africa which was not a member of the AU, following its withdrawal from the OAU in 1984. Many leaders of African nations supported the reintegration of Morocco to the AU. In July 2016, Morocco announced that it wished to rejoin the organization. Morocco's membership was approved by the AU on 30 January 2017.
Possible growth.
In February 2012, the Caribbean Republic of Haiti signalled that it would seek to upgrade its observer status to associate member status. The AU had planned at its summit in June 2013 to upgrade Haiti's status from observer to associate. In a press release issued May 2016, the African Union Commission announced that, "[a]ccording to Article 29.1 of the AU’s Constitutive Act, only African States can join the African Union." Therefore, "Haiti will not be admitted as a Member State of the African Union".
Although the AU includes one largely unrecognised state, the Sahrawi Arab Democratic Republic, the prospects of the unrecognised African state of Somaliland being admitted to the organisation are slim. The AU continues to recognise the territorial integrity of Somalia, favouring the Transitional Federal Government's claim that Somaliland is an autonomous region over the Somaliland government's assertion of full sovereignty. Nonetheless, Somaliland applied for AU membership in 2005, a request that has hereto gone unanswered.
After Azawad's unilateral declaration of independence from Mali in 2012, the AU issued a statement calling the pronouncement "null and of no value whatsoever".
The only parts of continental Africa or outlying islands not represented by the AU are dependencies and other small territories of France (Mayotte, Réunion, and the Scattered Islands in the Indian Ocean), Italy (Pantelleria and the Pelagie Islands), Portugal (Madeira Islands), Spain (Canary Islands, Ceuta, Melilla, and the plazas de soberanía), the United Kingdom (Saint Helena, Ascension and Tristan da Cunha, Chagos Archipelago), and Yemen (Socotra). Spain's Ceuta and Melilla are the only territories on continental Africa not represented by an AU member state.
Israel's PM Benjamin Netanyahu has requested to join the African Union as an observer, with the bid supported by Ghana.