Castrillón is a Spanish surname. Notable people with the surname include:
Álvaro Mejía Castrillón (born 1967), Colombian road bicycle racer
Jaime Castrillón (born 1983), Colombian footballer
Manuel Fernández Castrillón (c. 1780–1836), major general in the Mexican army
Eduardo Crespo y García-Castrillón, 8th Count of Castillo Fiel (fl. 1963–1989), Spanish aristocrat
Darío Castrillón Hoyos (born 1929), Colombian Cardinal of the Catholic Church