The Japan Series (日本選手権シリーズ試合 Nihon Senshuken Shiriizu Shiai, usually shortened to Nihon Shiriizu) is a seven-game championship played by the winners of Japan's two professional baseball leagues (the Central League and Pacific League). It is usually played in October.

The 2003 Japan Series champions were the Fukuoka Daiei Hawks, who defeated the Hanshin Tigers 4-2.