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

Graduated in Law, Caetano was a professor at the Law School of the University of Lisbon. An ultraconservative politician, by 1940 Caetano started his political career under the authoritarian dictatorship of António de Oliveira Salazar. He soon become an important figure in the "Estado Novo" regime and was appointed chief of the Mocidade Portuguesa (Portuguese Youth), and 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 only made small gestures, such as change the name of the secret police from PIDE to DGS and allow some controled opposition in the election in 1969.

Since the beginning of the 1960s, the Portuguese colonies in Africa (Angola, Mozambique and Cabo Verde) were struggling for independence, but the Lisbon government was not willing to concede and Salazar sent troops to fight the independence movements. By 1970, the war in Africa was consuming as much as 40% of the Portuguese budget and there was no sign of a solution in sight.

By the beginning of 1974, signals of rebellion increased. A movement named "Movimento das Forças Armadas" (MFA) was formed within the army and started planning a coup d'état to end the "Estado Novo" regime. In March, an unsuccessful attempt against the regime was made. But on April 25, the military 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.