X-Men: Mutant Wars is a side-scrolling beat 'em up game for Game Boy Color released in 2000. It is the second X-Men titled released for the system. It was released to coincide with the release of the X-Men film on DVD.

Characters can be changed at any time during the game, which is important as their power level decreases through the game. When the player changes character, those are not being controlled will gradually recover their power level. Also, some areas can only be completed by using the unique abilities of certain characters.

An alternate game mode has the player facing all the boss characters from the main game, and if the current character runs out of power, they cannot be used again.