The Derg (also spelled Dergue; Amharic: ደርግ, lit. 'committee' or 'council'), officially the Provisional Military Administrative Council (PMAC), was the military junta that ruled Ethiopia, then including present-day Eritrea, from 1974 to 1987, when the military leadership formally "civilianized" the administration but stayed in power until 1991.

The Derg was established in June 1974 as the Coordinating Committee of the Armed Forces, Police and Territorial Army, by officers of the Ethiopian Army and Police led initially by chairman Mengistu Haile Mariam. On 12 September 1974, the Derg overthrew the government of the Ethiopian Empire and Emperor Haile Selassie during nationwide mass protests, and three days later formally renamed itself the Provisional Military Administrative Council. In March 1975 the Derg abolished the monarchy and established Ethiopia as a Marxist-Leninist state with itself as the vanguard party in a provisional government. The abolition of feudalism, increased literacy, nationalization, and sweeping land reform including the resettlement and villagization from the Ethiopian Highlands became priorities. Mengistu became chairman in 1977, launching the Red Terror (Qey Shibir) political repression campaign to eliminate political opponents, with tens of thousands imprisoned and executed without trial.

By the mid-1980s, Ethiopia was plagued by multiple issues, such as droughts, economic decline and increasing reliance on foreign aid, recovering from the Ogaden War, and the 1983–1985 famine from which the Derg itself estimated more than a million deaths during its time in power. Conflicts between the Derg and various ethnic militias saw a gradual resurgence, particularly the Ethiopian Civil War and the Eritrean War of Independence. Mengistu abolished the Derg in 1987 and formed the People's Democratic Republic of Ethiopia led by the Workers' Party of Ethiopia, with a new government containing civilians but still dominated by members of the Derg.