Nigerian military juntas of 1966–79 and 1983–98

The two Nigerian Military Juntas of 1966-1979 and 1983-1998 were a pair of military dictatorships in the African country of Nigeria that were led by the Nigerian Military, having a chairman or president in charge.

First Junta (1966–1979)
The first one began on January 15, 1966, when Major Chukwuma Nzeogwu and some group of Majors overthrew current president Nnamdi Azikiwe in a coup d'état, and declared himself Head of the Federal Military Government of Nigeria. Aguiyi-Ironisi was then overthrown and murdered in a coup the same year by General Yakubu Gowon, who held power until 1975 when he was overthrown in a bloodless coup by a group of soldiers that wanted to return civilian rule to Nigeria. Brigadier (later General) Murtala Mohammed, who succeeded General Gowon, was not directly involved in this coup, but did help round up soldiers for the coup. A year later, in 1976, Mohammed was assassinated in a violent coup, and Olusẹgun Ọbasanjọ then succeeded Mohammed. Three years later, in 1979, Ọbasanjọ handed power down to Shehu Shagari, who ended the military regime, and installed a second Nigerian republic.

Second Junta (1983–1998)
Shagari, however, was overthrown in a bloodless coup in 1983, and succeeded by Muhammadu Buhari, who was appointed Chairman of the Supreme Military Council of Nigeria and Commander-in-Chief of the Armed Forces by the junta. Buhari ruled for two years, until 1985, when he was overthrown by General Ibrahim Babangida, who appointed himself with the position of President of the Armed Forces Ruling Council of Nigeria. Babangida promised a return of democracy when he seized power, which barely took place during the Babangida regime. He ruled Nigeria until 1993 when he temporarily handed power to the interim head of state Ernest Shonekan, being part of his promise to return democracy. Two months later, however, Shonekan was overthrown by General Sani Abacha, with former President Babangida conveniently involved with a visit to Egypt. Abacha appointed himself Chairman of the Provisional Ruling Council of Nigeria. After Abacha's death in 1998, General Abdulsalami Abubakar took over, and ruled until 1999 when Olusẹgun Ọbasanjọ again became head of state (via an election), and ended the junta. Olusegun Obasanjo ruled until 2007 and then passed it down to another democratically elected president Umaru Musa Yar'adua who ruled Nigeria until his death in 2010.