The Carnation Revolution, also known as the 25 April, was a military coup by military officers that overthrew the authoritarian Estado Novo government on 25 April 1974 in Lisbon, producing major social, economic, territorial, demographic, and political changes in Portugal and its overseas colonies through the Processo Revolucionário Em Curso. It resulted in the Portuguese transition to democracy and the end of the Portuguese Colonial War.

The Estado Novo was the corporatist Portuguese state installed in 1933. It evolved from the Ditadura Nacional formed after the coup d'état of 28 May 1926 against the unstable First Republic. Together, the Ditadura Nacional and the Estado Novo are recognised by historians as the Second Portuguese Republic. The Estado Novo, greatly inspired by conservative and autocratic ideologies, was developed by António de Oliveira Salazar, who was President of the Council of Ministers from 1932 until illness forced him out of office in 1968.