Marcelo Caetano also spelled Marcello Caetano (August 17, 1906- October 26, 1980) was a Portuguese politician.

Graduated in Law, Caetano was a teacher in the Law School of Lisbon. An ultraconservative politician, by 1940 Caetano started his political career in the authoritarian dictatorship of António de Oliveira Salazar. He soon become an important figure in the "Estado Novo" regime, being appointed to be the chief of Mocidade Portuguesa (Portuguese Youth), after that, Minister of the Colonies.

In 1968, Salazar suddenly suffered a stroke after falling from a chair, and after 36 years as prime minister, he was removed from power. President Admiral Américo Thomaz appointed Caetano to replace Salazar in September 28, 1968. Portuguese people hoped that the new prime-minister would soften the authoritarian regime and modernize the stagnant economy, but Caetano olny did small gestures, such as change the name of the political policy from PIDE to DGS and allow some controled opposition in the election in 1969.

Since the beggining of the 1960s, the Portuguese colonies in Africa (Angola, Mozambique and Cabo Verde) were struggling for independence, but the Lisbon government wasn't willing to concede and Salazar send troops to fight against the rebels. By 1970, the war in Africa was consuming as much as 40% of the Portuguese budget and there was no sign of victory in sight.

By the beginning of 1974, signals of rebellion increased. Among the army, surged a moviment called "Movimento das Forças Armadas" (MFA), that started planning the fall of the "Estado Novo". In march, an unsuccessful attempt against the regime was made. But on April 25, the militars overthrew and imprisioned Caetano, in the "Carnation Revolution" that ended 48 years of dictatorship in Portugal.

Caetano soon fled to exile in Brazil, where he died a few years later.