Muhammadu Buhari (born December 17, 1942) was a military ruler of Nigeria (1983 - 1985) and an unsuccessful candidate for president in 2003. He is a Fulani Muslim from Katsina State .

Buhari and Chief of staff General Tunde Idiagbon led a successful military coup d'etat that overthrew civilian President Shehu Shagari on December 31, 1983. Buhari justified his seizure of power by castigating the civilian government as hopelessly corrupt, and Idiagbon subsequently initiated a War Against Indiscipline (WAI) that was sharply authoritarian and mostly dispensed with due process in the prosecution of politicians and bureaucrats for corruption. But it is still argued by many to be the most orderly Nigeria has ever been in the last 40 years.

Buhari and Idiagbon's WAI was initially popular with the majority of Nigerians, and nothing like has been put in place since. However, this support quickly ebbed away as Buhari resorted to ever more severe methods to stifle criticism of his government, including the issuing of the State Security (Detention of Persons) Decree No. 2, which gave the government the right to detain indefinitely without trial any persons it regarded as being a threat to the nation, and the Public Officers (Protection Against False Accusation) Decree No. 4, which essentially criminalized any criticism of government officials in the press. Buhari was himself overthrown in a coup by General Ibrahim Babangida on August 27, 1985.

In 2003, Buhari contested the Presidential election as the candidate of the All Nigerian People's Party . He was defeated by the incumbent President, Olusegun Obasanjo, by a margin of more than eleven million votes. Although there were allegations of fraud, the general consensus among Commonwealth observers was that the result was so decisive that fraud, on either side, would not have substantially affected it. More disturbing to many observers was the evident polarization of the country along religious lines, with the Muslim north voting overwhelmingly for Buhari and the largely Christian south for Obasanjo. Many wondered whether a country so evenly divided between two major religions could afford such polarization.