Uruguayan leftist urban guerrilla organization founded in about 1963. The group was named for Tupac Amaru II, the leader of an 18th-century revolt against Spanish rule in Peru.

The chief founder of Tupamaro was Raúl Sendic (Sendic, Raúl), a labour organizer. The earliest Tupamaro efforts were a mixture of idealism, public relations, and theft—robbing banks and businesses and distributing food and goods to the poor. In 1968 Tupamaro began more earnest efforts to undermine the established order, including raids on arsenals, arson, and kidnappings and assassinations of police and government officials. The organization also carried out bombings against foreign interests, particularly those of Brazil and the United States. In 1971 it kidnapped the British ambassador and held him for eight months. Its success was brief, however; by the time of the June 1973 military coup in Uruguay, Tupamaro had been neutralized by government troops, which managed to kill some 300 members and imprison nearly 3,000 others. After democratic rule returned to Uruguay in 1985, most of those jailed, including Sendic, were released under a general amnesty, and Tupamaro was reorganized as a legal political party.