The military history of Brazil comprises centuries of armed actions in the territory encompassing modern Brazil, and the role of the Brazilian Armed Forces in conflicts and peacekeeping worldwide. For several hundreds of years, the area was the site of intertribal wars of indigenous peoples. Beginning in the 16th century, the arrival of Portuguese explorers led to conflicts with the indigenous peoples; a notable example being the revolt of the Tamoio Confederation. Sporadic revolts of African slaves also marked the colonial period, with a notable rebellion led by Zumbi dos Palmares. Conflicts were fought with other European nations as well – two notable examples being the France Antarctique affair, and a conflict with the Netherlands in the early 17th century over control of much of Northeastern Brazil. Although Portugal retained its possessions during conflicts with other nations, it lost control of the colony after the Brazilian war of Independence, which led to the establishment of the Empire of Brazil.

The Brazilian Armed Forces are the unified military forces of the Federative Republic of Brazil. Consisting of three service branches, it comprises the Brazilian Army, the Brazilian Navy and the Brazilian Air Force.