Jânio da Silva Quadros (January 25, 1917—February 16, 1992) was a Brazilian politician who was briefly President of Brazil in 1961.

Quadros was born in Campo Grande, Mato Grosso do Sul. With populist rhetoric and extravagant behavior, he had a meteoric career: he became mayor of the city of São Paulo in 1953, governor of São Paulo state in 1955, and was elected president of Brazil by a landslide in 1960, taking office on January 31, 1961.

He blamed his predecessor, Juscelino Kubitschek, for high inflation. During his time in office, Quadros outlawed gambling, banned women from wearing bikinis on the beach, and established relations with the Soviet Union and Cuba. In a move supposed to gain him more power, he resigned on August 25, 1961, expecting to return to the presidency by acclamation of the Brazilian people. But this move was immediately rejected by the Congress, which called the leftist vice-president João Goulart to take the office instead. Quadros' resignation started a severe political crisis that culminated in a military coup in 1964. The military did not allow Quadros to return to politics, but by the 1980s he was back and was elected mayor of São Paulo in 1985, defeating Fernando Henrique Cardoso.

See also: List of Presidents of Brazil