1939 Major League Baseball season

The regular season ended on October 1, with the Cincinnati Reds and New York Yankees as the regular season champions of the National League and American League, respectively.

The Yankees swept the Reds in four games, capturing their eighth championship in franchise history, and their last in a four-World Series run, becoming the first team to win four consecutive World Series.

This continued the trend from the previous season which saw both leagues opened on different days.

The final day of the regular season was on October 1 and featured twelve teams.

The 1939 season saw the following rule change: An asterisk (*) denotes the ballpark a team played the minority of their home games at *Denotes walk-off 1 National League Triple Crown pitching winner