Sid Ahmed Ould Bneijara (born 1947) was briefly the 4th Prime Minister of Mauritania from December 12, 1980 to April 25, 1981.
He was first appointed by Col. Mohamed Khouna Ould Haidallah of the Military Committee for National Salvation (CMSN), on December 12, 1980, to replace Haidallah himself. Ould Bneijara, who was not a military man, was to lead the return to civilian government.
On April 25, 1981, less than five months later, Ould Bneijara was again dismissed, after Col. Haidallah had decided to reinstate military rule. This came as a result of the March 18 attempt at a coup d'état by the Alliance for a Democratic Mauritania (AMD). His successor, Col. Maaouia Ould Taya, would in 1984 depose Col. Haidallah and himself rule the country until 2005.