Chichimeca (Spanish [tʃitʃiˈmeka] ) was the name that the Nahua peoples of Mexico generically applied to nomadic and semi-nomadic peoples who were established in present-day Bajio region of Mexico. Chichimeca carried the same sense as the Roman term "barbarian" to describe Germanic tribes. The name and its pejorative sense was adopted by the Spanish. For the Spanish, in the words of scholar Charlotte M. Gradie, "the Chichimecas were a wild, nomadic people who lived north of the Valley of Mexico. They had no fixed dwelling places, lived by hunting, wore little clothes and fiercely resisted foreign intrusion into their territory, which happened to contain silver mines the Spanish wished to exploit."
In modern times only one ethnic group is customarily referred to as Chichimecs, namely the Chichimeca Jonaz of whom a few thousand live in the state of Guanajuato.
The Chichimeca peoples were primarily of eight nations that spoke different languages. As the Spaniards worked towards consolidating the rule of New Spain over the indigenous peoples during the sixteenth and seventeenth centuries, the Chichimecan nations resisted fiercely. A number of native groups of the region allied with the Spanish. The most long-lasting of these conflicts (1550–91) was the Chichimeca War, resulting in the defeat of the Spanish Empire and a decisive victory for the Chichimeca Confederation.