Guaraní-speaking South American Indians living in the Bolivian foothills of the eastern Andes and in Argentina. They are linguistically and culturally related to the Tupí-Guaraní horticulturists living throughout the tropical rain forests of the Amazon basin. Chiriguano is a term used by outsiders; the group prefers the ethnonym Guaraní.

During the late 15th and early 16th centuries, the ancestors of the group left Paraguay, crossed the Gran Chaco, and settled in their present homeland. In the course of these migrations, they conquered, enslaved, and absorbed thousands of Arawakan-speaking Chane farmers who lived in the northern stretch of the Chaco and who had been strongly influenced by Inca civilization for many years. Although they were the westernmost of the Tupí-Guaranian peoples and came into the closest contact with the civilizations of the Andes, the Chiriguano were not influenced as directly by the Inca as they were by the Chane.

By the late 20th century the group had intermarried with Bolivians, Paraguayans, Chane, and other Andean populations; many of their number had emigrated to Argentina to find employment in sugar factories. They had also joined with other Guaraní speakers to create a pan-national identity, mobilize political power, and ensure political self-determination. Guaraní speakers were estimated to number some 50,000 individuals in the early 21st century.