AREX is a South Korean railway line that links Seoul with Gimpo Airport and Incheon International Airport.
Arex may also refer to:
Arex (Star Trek character), a character from Star Trek: The Animated Series Administrative Records Experiment, a project designed to explore alternatives to the 2010 United States Census Arex, one of Marvel's Eternals (comics)
See also ARexx, an implementation of the REXX language for Commodore Amiga computers