Casillas is a Spanish surname that may refer to
Andrés Casillas de Alba (born 1934), Mexican architect Giovani Casillas (born 1994), Mexican association football player Graciela Casillas (born 1957), American boxer and kickboxer Hugo Casillas (born 1981), Mexican association football player Iker Casillas (born 1981), Spanish football goalkeeper Jesús Casillas Romero (born 1962), Mexican politician Luis Casíllas (1905–?), Mexican modern pentathlete Martín Casillas (1556–1618), Spanish architect Jonathan Casillas (born 1987), American football linebacker
Susana Casillas, Mexican visual artist Toñín Casillas (born 1935), Puerto Rican basketball player Tony Casillas (born 1963), American football defensive lineman