Montenegro is a city and municipality of the state of Rio Grande do Sul, Brazil.

The town was established in 1847 to be settled primarily by German immigrants from the Husrück region of southwest Germany. The local language was Riograndenser Hunsrückisch for most of its history and is still spoken there after 150 years of the initial settlement. Although today Portuguese prevails, mostly as a result of the campaign of the "Nationalization" (Nacionalização) forcefully imposed on all German and Italian settled areas of southern Brazil by president and dictator Getúlio Vargas in the 1940s.

Cardinal Cláudio Hummes, one of the candidates to the Catholic Church papacy in April of 2005 was born in the area.