Calixto Oriola Zaldivar (September 13, 1904 – October 13, 1979) was a Filipino lawyer and politician who was a Supreme Court Justice from 1964 to 1974 best known in Philippine history for being one of only four dissenting voices against the constitutionality of the Philippines' 1973 constitution in the 1973 case known as Javellana v. Executive Secretary, despite pressure by the authoritarian government of Ferdinand Marcos to vote in the constitution's favor.