1921 Major League Baseball season

The 1921 major league baseball season began on April 13, 1921. The regular season ended on October 2, with the New York Giants and New York Yankees as the regular season champions of the National League and American League, respectively. The postseason began with Game 1 of the 18th World Series on October 5 and ended with Game 8 on October 13. The Giants defeated the Yankees, five games to three.

1921 was the first of three straight seasons in which the Yankees would lead the majors in wins. Babe Ruth broke the single season home run record for the third consecutive season by hitting 59 home runs in 152 games. Ruth also broke Roger Connor's record for the most home runs all time when he hit his 139th home run on July 18 against Bert Cole. The record for career strikeouts, previously held by Cy Young was also broken in 1921 by Walter Johnson; Johnson led the league in strikeouts with 143 and ended the season with 2,835 strikeouts. Young struck out 2,803 during his career. The Cincinnati Reds set a Major League record for the fewest strikeouts in a season, with only 308. Future Hall of Famers Kiki Cuyler and Goose Goslin both debuted in September 1921.

Schedule
The 1921 schedule consisted of 154 games for all teams in the American League and National League, each of which had eight teams. Each team was scheduled to play 22 games against the other seven teams of their respective league. This continued the format put in place since the season (except for ) and would be used until  in the American League and  in the National League.

Opening Day took place on April 13 with all but the Chicago White Sox and Detroit Tigers playing. The final day of the regular season was on October 2. The World Series took place between October 5 and October 13.

Bracket
 

Events

 * August 5 – The Pittsburgh Pirates 8–5 victory over the Philadelphia Phillies at Forbes Field is the first Major League game to be broadcast on radio. Harold Arlin calls the game for Pittsburgh station KDKA.