Moktar Ould Daddah (Arabic: مختار ولد داداه, romanized: Mukhtār Wald Dāddāh; 25 December 1924 – 14 October 2003) was a Mauritanian politician who served as the country's first President after it gained its independence from France. Moktar served as the country's first Prime Minister from 1957 to 1961 and as its first President of Mauritania, a position he held for 18 years until he was deposed in a military coup d'etat in 1978.

He established an authoritarian one-party state, with his Mauritanian People's Party being the sole legal political entity in the country, and followed a policy of "Islamic socialism" with many nationalizations of private businesses. In his memoirs, Moktar expressed concern that the issue of slavery in Mauritania could lead to armed conflict that would ultimately destroy the country.

In foreign affairs, he joined the Non-Aligned Movement and maintained strong links with Mao Zedong and the People's Republic of China, but he also accepted Western (especially French) foreign aid. During his presidency, Mauritania saw conflict with the Polisario Front in Western Sahara after working to broker a deal to divide the territory with Morocco.

Moktar was born to an important marabout family of the Ouled Birri tribe in Boutilimit, Mauritania, French West Africa. After attending elite Islamic academies, he worked for the French colonial administrators as a translator.

As a law student in Paris, he graduated as the first Mauritanian to hold a University Degree. He was later admitted to the bar at Dakar, Senegal in 1955. Upon his return to Mauritania in the late 1950s, Moktar joined the centre-left Mauritanian Progressive Union, and was elected President of its Executive Council. In 1959, however, he established a new political party, the Mauritanian Regroupment Party. In the last pre-independence legislative elections held later that year, his party won every seat in the National Assembly, and he was appointed Prime Minister.

He was known for his ability to establish a consensus among different political parties, as well as between the White Moors, Black Moors and Black Africans, Mauritania's three main ethnic groups. The balanced representation of different ethnic and political groups in his government won the confidence of the French authorities, who granted independence to Mauritania under his leadership in 1960. Moktar was named Acting President of the new Islamic Republic, and was confirmed in office in the first post-independence election in August 1961.

As President, Moktar pursued policies that differed markedly from those he had professed prior to independence. In September 1961, he formed a "Government of National Unity" with the main opposition party, and in December, he arranged for the four largest parties to merge as the Mauritanian People's Party (PPM), which became the sole legal party. He formalized the one-party state in 1964 with a new Constitution, which set up an authoritarian presidential regime. Moktar justified this decision on the grounds that he considered Mauritania unready for western-style multi-party democracy.

Under this one-party constitution, Moktar was reelected in uncontested elections in 1966, 1971 and 1976.