The 1907 major league baseball season began on April 11, 1907. The regular season ended on October 6, with the Chicago Cubs and Detroit Tigers as regular season champions of the National League and American League, respectively. The postseason began with Game 1 of the fourth modern World Series on October 8 and ended with Game 5 on October 12. The Cubs defeated the Tigers, four games to none, capturing their first championship in franchise history. Going into the season, the defending World Series champions were the Chicago White Sox from the 1906 season.