The following are the baseball events of the year 1906 throughout the world.
Inter-league playoff: Chicago (AL) declined challenge by New York Giants.
Major league baseball final standings
American League final standings
National League final standings
- May 8 – Philadelphia Athletics manager Connie Mack needed a substitute outfielder in the sixth inning of a game against the Boston Pilgrims and called on pitcher Chief Bender to fill in. Bender hit two home runs, both inside the park.
- July 4 – Mordecai Brown of the Chicago Cubs defeats Lefty Leifield of the Pittsburgh Pirates 1-0, in the first game of a doubleheader, in which both pitchers throw a 1-hitter. Leifield collects the Pirates only hit off Brown and loses his own bid for a no-hitter by giving up a single in the 9th inning that ends up scoring the only run of the game.
- July 20 – Mal Eason tosses a no hitter for the Brooklyn Superbas, as they defeat the St. Louis Cardinals, 2-0.
- August 1 – Brooklyn Superbas pitcher Harry McIntire would not allow a hit to the Pittsburgh Pirates through 10 innings, only to allow a single with two outs in the 11th inning. McIntire would allow three more hits before the Pirates outlasted the Superbas, 1-0, in 13 innings.
- August 3 – At Sportsman's Park, Long Tom Hughes of the Washington Senators and Fred Glade of the St. Louis Browns entered the 10th inning with a scoreless tie, until Hughes decided the game with a solo home run to a 1–0 victory, becoming the first pitcher in major league history to pitch a shutout and hit a home run which accounted for the only run in the game.
- September 1 – The Philadelphia A's Jack Coombs and the Boston Pilgrims' Joe Harris each pitch all 24 innings of the A's 4–1 victory over the Pilgrims at Boston's Huntingdon Avenue Grounds. Coombs and Harris still hold the American League record. The major league record is held by the Brooklyn Dodgers' Leon Cadore and Boston Braves' Joe Oeschger, who battled to a 26-inning, 1–1 deadlock on May 1, 1920.
- October 14 – In perhaps the greatest upset in World Series history, the Chicago White Sox (93 wins) defeated the Chicago Cubs (116 wins), 8–3, in Game 6, winning the World Championship, four games to two, despite hitting only .198 and committing 15 errors in the series.
- January 26 – Fred Underwood, 37, pitcher for the 1894 Brooklyn Grooms;
- February 16 – Yale Murphy, 36, shortstop and outfielder who played from 1894 through 1897 for the New York Giants.
- February 18 – Charlie Ingraham, 45, catcher for the 1883 Baltimore Orioles.
- February 27 – John Peltz, 44, outfielder who played with the Hoosiers, Orioles, Gladiators, Stars and Maunees between the 1884 and 1890 seasons.
- March 25 – Joe Cassidy, 23, shortstop for the Senators since 1904 who led AL with 19 triples as a rookie, led league in assists in 1905.
- March 27 – Toad Ramsey, 41, pitcher for Louisville who topped 35 wins in both 1886 and 1887, with strikeout totals of 499 and 355.
- June 14 – Mike Sullivan, 39, pitcher who posted a 54–65 record and a 5.04 ERA with eight teams from 1889 to 1899.
- June 15 – Sandy Nava, 56, catcher and first known Mexican American to play in the Majors.
- June 24 – Joe Strauss, 47, left fielder/catcher/pitcher for the Colonels/Cowboys/Grays from 1884 to 1886.
- August 16 – Tom Carey, 60, 19th century infielder and player-manager.
- October 20 – Buck Ewing, 47, catcher, most notably for the New York Giants, who batted .303 lifetime and led NL in home runs and triples once each; captain of 1888–89 NL champions batted .346 in 1888. championship series; in 1883 was one of the first two players to hit 10 home runs in a season; led NL in assists three times and double plays twice, was later Cincinnati manager.
- September – Matthew Porter, 47, player-manager for the 1884 Kansas City Cowboys of the Union Association.
- August 31 – Alex Voss, 48, utility for the Nationals and Cowboys in the 1884 season.
- September 22 – George Davies, 38, pitcher who posted an 18–24 record and a 3.32 ERA for the Spiders, Brewers and Giants from 1891 to 1893.
- November 22 – Tom Cotter, 40, catcher who played six games for the 1891 Boston Reds.
- October 25 – Marty Swandell, 65, infielder/outfielder for the Eckfords and Resolutes from 1872 to 1873.
- November 22 – Tom Cotter, 40, catcher for the 1891 Champions Boston Reds.
- November 27 – Julius Willigrod, 49, outfielder/shortstop who played with the Wolverines and Blues in the 1882 season.
- December 19 – Ed Pinkham, 60, third baseman for the 1871 Chicago White Stockings.
- December 30 – Henry Porter, 48, pitcher for three teams in the 1880s, who set a major league record for an 18-strikeout game for a losing pitcher in 1884 and also threw a no-hitter in 1888.