Quechua (Runa Simi, 'language of the people') is a family of closely related languages rather than a single tongue, spoken throughout the Andes. Linguists divide it into two major branches, Quechua I (Central, in Peru's central highlands) and Quechua II (Northern and Southern), with its original homeland probably on the central Peruvian coast or highlands, not Cuzco. Although often associated with the Inca Empire, Quechua long predates it and spread both before and after the Inca era.

Quechua is the most widely spoken Indigenous language of the Americas, with roughly 8 to 10 million speakers across Peru, Bolivia, Ecuador, and parts of Argentina, Colombia and Chile. Its speakers form diverse Andean peoples tied to high-altitude agriculture (potatoes, maize, quinoa), camelid herding, and communal forms of organization such as the ayllu and reciprocity (ayni, minka). This vast distribution reflects centuries of Inca, colonial and later expansion.

After the conquest of Tawantinsuyu in the 1530s, the Spanish adopted Quechua as a 'general language' for administration and evangelization, which paradoxically spread it to regions where it had not previously been spoken. The Church produced grammars, vocabularies and catechisms, such as that of Domingo de Santo Tomás (1560), the first printed record of the language. However, after the rebellion of Túpac Amaru II in 1781, the crown restricted Quechua, beginning a long period of stigmatization.

Quechua is an official or co-official language in Peru, Bolivia and Ecuador, though its vitality varies: it is robust in many rural areas but receding in cities and among the young under pressure from Spanish. There are intercultural bilingual education programs, media, translations, and a growing presence online and in popular music. Cultural and academic initiatives, together with renewed identity pride, drive its revitalization, although dialectal fragmentation poses challenges for a common standard.