Ahmedou Ould-Abdallah (born November 21, 1940), is a Mauritanian diplomat and United Nations official.

Ould-Abdallah graduated from secondary school in Dakar, Senegal. He studied economics at the University of Grenoble and the University of Paris and political science at the Sorbonne and has held several cabinet-level posts in the Mauritanian government, including that of Minister for Foreign Affairs and Cooperation. He has also been Mauritania's ambassador to Belgium, Luxembourg, and the Netherlands, the European Union and to the United States.

Ould-Abdallah was in charge of African economic affairs at the United Nations for six years and from 1993 to 1995 was Secretary General Boutros Boutros-Ghali's Special Representative for Burundi during the first part of the Burundi Civil War. In 2002, Secretary General Kofi Annan appointed him Special Representative for West Africa at the head of the United Nations Office for West Africa.