| John Slappey | |
| Position: | Pitcher |
| Bats: | Left |
| Throws: | Left |
| Birth Date: | 8 August 1898 |
| Birth Place: | Albany, Georgia |
| Death Place: | Marietta, Georgia |
| Debutleague: | MLB |
| Debutdate: | August 23 |
| Debutteam: | Philadelphia Athletics |
| Finalleague: | MLB |
| Finaldate: | October 2 |
| Finalteam: | Philadelphia Athletics |
| Statleague: | MLB |
| Stat1label: | Win–loss record |
| Stat1value: | 0-1 |
| Stat2label: | Earned run average |
| Stat2value: | 7.11 |
| Stat3label: | Strikeouts |
| Stat3value: | 1 |
| Teams: | |
John Henry Slappey (August 8, 1898 – June 10, 1957) was a Major League Baseball pitcher who played in with the Philadelphia Athletics.