1888 Major League Baseball season
| 1888 MLB season | |
|---|---|
| League | American Association (AA) National League (NL) |
| Sport | Baseball |
| Duration | Regular season:
|
| Number of games | 140 |
| Number of teams | 16 (8 per league) |
| Pennant winner | |
| AA champions | St. Louis Browns |
| AA runners-up | Brooklyn Bridegrooms |
| NL champions | New York Giants |
| NL runners-up | Chicago White Stockings |
| World's Championship Series | |
| Champions | New York Giants |
| Runners-up | St. Louis Browns |
The 1888 major league baseball season began on April 18, 1888. The regular season ended on October 17, with the New York Giants and the St. Louis Browns as regular season champions of the National League and American Association, respectively. The postseason began with Game 1 of the fifth World's Championship Series on October 16 and ended with Game 10 on October 27, in what was a best-of-eleven-playoff. The Giants defeated the Browns, six games to four, capturing their first World's Championship Series.
Over the offseason, the American Association's New York Metropolitans folded, and saw them replaced by the newly enfranchised Kansas City Cowboys. Meanwhile, the Brooklyn Grays renamed as the Brooklyn Bridegrooms.