Field Marshal Humberto de Alencar Castelo Branco (Portuguese pronunciation: ũˈbɛʁtu dʒi alẽˈkaʁ kasˈtɛlu ˈbɾɐ͂ku; September 20, 1897 - July 18, 1967) was a Brazilian military leader and politician. Castelo Branco entered the Brazilian Army in 1918 and was a colonel in the Brazilian Expeditionary Force during World War II. Appointed Chief of Staff of the Army by President João Goulart in 1963, he became one of the leaders of the coup d'etat of March 31, 1964 that overthrew Goulart. Elected president by the Congress, he took the oath of office on April 15, 1964 and served until March 15, 1967.

Castelo Branco was the second Brazilian Field Marshal to become president of the nation through a coup d'état—the first was Deodoro da Fonseca, who deposed the Monarchic government of Emperor D. Pedro II in 1889. Castello Branco’s government, differently from previous directly-elected presidents Juscelino Kubitschek, Jânio Quadros and João Goulart, was bankrolled from the start by the credits and loans from World Bank, IMF and massive investment from multinational American companies, which saw the Brazilian right-wing military dictatorship as a new, economically-stable Western ally against international Communism—mainly in Latin America—during the Cold War. During his term, Castelo Branco dismantled the left wing of Congress, abolished all existing political parties, and replaced them with only two: the government party, called the "National Renewal Alliance Party" (ARENA) and the opposition "Brazilian Democratic Movement" (MDB). He promoted government intervention into the economy (e.g. shutting down by decree the country's flag carrier, Panair do Brasil) and tributary reforms. He was succeeded by his war minister Marshal Artur da Costa e Silva. Castelo Branco was also responsible for the promulgation of a restrictive Brazilian press law (Lei de Imprensa) at the end of his administration in 1967. This law continued to be valid in Brazil until 2009, when it was struck down by Brazil’s Supreme Federal Court. Shortly after leaving the presidency, he died in an air crash near Fortaleza.