Three-dimensional chess is any chess variant that replaces the two-dimensional board with a three-dimensional array of cells between which the pieces can move. In practice, this is usually achieved by boards representing different layers being laid out next to each other. Three-dimensional chess has often appeared in science fiction—the Star Trek franchise in particular—contributing to the game's familiarity.

A chess variant is a game related to, derived from, or inspired by chess. Such variants can differ from chess in many different ways.