The following are the baseball events of the year 1912 throughout the world.
- Three clubs opened brand-new ballparks in this season.
- In response to the demand for an alternative way to statistically rate pitchers, the National League elected to officially score the Earned Run Average for the first time. New York Giants pitcher Jeff Tesreau went on to lead the new category with a 1.96 ERA.
U.S. president Taft at a Washington-Chicago game, August 13
- October 16 – The Boston Red Sox defeat the New York Giants, 3–2, in Game 8 of the World Series, ending one of the most exciting Series in Major League history. The Red Sox win the World Championship four games to three, with Game 2 being declared a tie. Nearly all of the contests were close, as four games in this series were decided by one run, a fifth ended in a tie, and a sixth was decided by two runs. Game 7 was the only one with a margin greater than three runs. Two games, including the decisive Game 8, went to extra innings. In Games 1 and 3, the losing team had the tying and winning runs on base when the game ended. This was the first time in which a World Series was decided in the last inning of the final game, in sudden death, or sudden victory fashion. It was also the first Series where a team within one inning of losing came back to win. The next time a team that close to elimination recovered to win was in Game 6 of the 1986 Series.