In the Spanish colonial caste system (castas), a criollo was a person of unmixed Spanish ancestry born in the colonies.

The word is often translated into English as Creole, but this word has a much broader meaning (see Creole peoples).

The word criollo retains the original meaning in several Spanish-speaking countries in the Americas, as well as in the Philippines. In some countries, however, the word criollo has in time come to have other meanings

The Criollos in the caste system

---

While the castas system was in force, the local-born criollos ranked strictly lower than governing peninsulares ("born in the Iberian Peninsula"), despite both being of unmixed Spanish ancestry.

By the 19th century, this discrimination eventually led the criollo to rebel against the Spanish rule. With the support of even lower classes — castizos, mestizos, cholos, mulatos, amerindians, zambos, and ultimately blacks, in descending rank order — they engaged Spain in the Mexican War of Independence (1810–1821) and the South American Wars of Independence (1810–1825), which ended with the break-up of former Spanish Empire in America into a number of independent republics.

The Criollos formed a significant portion of the priestly class in Spanish Mexico and today are the direct descendants of the Spanish Conquest of Mexico.

Ethnic groups in Mexico | Ethnic groups in South America