The 28 May 1926 coup d'état, sometimes called 28 May Revolution or, during the period of the corporatist Estado Novo, the National Revolution, was a military coup of a nationalist origin, that put an end to the unstable Portuguese First Republic and initiated 48 years of corporatist and nationalist rule within Portugal. The regime that immediately resulted from the coup, the Ditadura Nacional, would be later refashioned into the Estado Novo, which in turn would last until the Carnation Revolution in 1974.

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.