Castizo (Spanish: [kasˈtiθo] or [kasˈtiso]) is a Spanish word with a general meaning of "pure" or "genuine". The feminine form is castiza. From this meaning it evolved other meanings, such as "typical of an area" and it was also used for one of the colonial Spanish race categories, the castas, that evolved in the 17th century.

Under the caste system of colonial Latin America, the term originally applied to the offspring resulting from the union of a European and a mestizo, that is, someone of three quarters European and one quarter Amerindian ancestry. During this era a myriad of other terms (mestizo, cuarterón de indio, etc.) were in use to denote other individuals of mixed European and Amerindian ancestry in ratios smaller or greater than that of castizos.

The term was mainly applied to mixed-race people who had a slightly darker complexion than what was assumed an unmixed Spaniard would have, but which were otherwise of European appearance with almost no visible admixture. Under this same caste system, the offspring of a Spaniard and a Castiza was classified as a criollo (legally, a Spaniard born in the Americas), thus the offspring regained his or her "purity of blood". (See the related concept of Limpieza de sangre.) For some castizos whose residual quarter of Amerindian ancestry was not apparent at all, many simply consolidated themselves within the criollos and Peninsulares (Spaniards born in Spain).