The King of Fighters 2003 (KOF 2003, or KOF '03), also known by fans as The King of Fighters X, is a fighting game produced by SNK Playmore for the Neo Geo arcade and home platforms in 2003. It is the tenth game in The King of Fighters series and the last one released for the Neo Geo, which served as the primary platform for the series since The King of Fighters '94. It was ported to the PlayStation 2 and Xbox (in North America and Japan only and it was not compatible with the Xbox 360), and was released in North America as a two-in-one bundle with the preceding game in the series, The King of Fighters 2002.
The game uses a 3-on-3 Tag Battle format in which players can change characters in the middle of a fight. Each team has one leader with access to a Leader Super Special Move. The narrative of the game involves a new tournament set by "R" with two parallel bosses serving as final bosses. The game is notable for starting the story arc of newcomer Ash Crimson, with the story arc itself titled the "Tales of Ash". Falcoon worked as the main illustrator. Critical reception to this game has been mixed due to the major change of the regular gameplay associated with the series.