Carlos Castañeda (11 November 1896 – 3 April 1958) was a historian, specializing in the history of Texas, and a leader in the push for civil rights for Mexican-Americans.
Born in Mexico, Castañeda immigrated to the United States with his family in 1908. He gained an undergraduate and master's degree in history from the University of Texas at Austin, and then spent several years teaching Spanish at the College of William and Mary. Castañeda returned to Texas in 1927, serving as the first curator of the Latin American collection at the University of Texas. While he worked as a librarian, Castañeda pursued his doctorate in history, which he finally earned in 1932.
Castañeda's work as a historian focused on the Spanish borderlands, especially Texas. He combed various archives in Mexico to find and copy previously unknown documentation on life in Texas and the southwestern United States. For his work in documenting Catholic history in Texas, Castañeda was named a Knight of the Holy Sepulchre and a Knight Commander in the Order of Isabella the Catholic of Spain.
During World War II, Castañeda took a leave of absence from his teaching position at the University of Texas to work as an investigator for the Fair Employment Practices Committee. He advocated for equal rights for Mexican-Americans, and was promoted to regional director of the FEPC southwest region in 1946.
The Perry–Castañeda Library at the University of Texas is named for him.