Mortal Kombat: Deception is a 2004 fighting game developed and published by Midway. It is the sixth main installment in the Mortal Kombat franchise and a sequel to 2002's Mortal Kombat: Deadly Alliance. It was released for the PlayStation 2 and Xbox in October 2004, for the GameCube in March 2005 and later ported for the PlayStation Portable under the title Mortal Kombat: Unchained in November 2006. Mortal Kombat: Deception follows the storyline from the fifth installment, Deadly Alliance. Its story centers on the revival of the Evil Dragon King Onaga, who attempts to conquer the realms featured in the series after defeating the sorcerers Quan Chi and Shang Tsung, the main antagonists in the previous game, and the Thunder God Raiden, defender of Earthrealm. The surviving warriors from the previous titles join forces to confront Onaga.

A fighting game is a genre of video game that involves combat between two or more characters. Fighting game combat often features mechanics such as blocking, grappling, counter-attacking, and chaining attacks together into "combos". Characters generally engage in battle using hand-to-hand combat—often some form of martial arts. The fighting game genre is related to, but distinct from, the beat 'em up genre, which pits large numbers of computer-controlled enemies against one or more player characters.