| Otto Rettig | |
| Position: | Pitcher |
| Bats: | Right |
| Throws: | Right |
| Birth Date: | 29 January 1894 |
| Birth Place: | New York City |
| Death Place: | Stuart, Florida |
| Debutleague: | MLB |
| Debutdate: | July 19 |
| Debutteam: | Philadelphia Athletics |
| Finalleague: | MLB |
| Finaldate: | August 5 |
| Finalteam: | Philadelphia Athletics |
| Statleague: | MLB |
| Stat1label: | Win–loss record |
| Stat1value: | 1-2 |
| Stat2label: | Earned run average |
| Stat2value: | 4.91 |
| Stat3label: | Strikeouts |
| Stat3value: | 3 |
| Teams: | |
Adolph John "Otto" Rettig (January 29, 1894 – June 16, 1977) was a Major League Baseball pitcher who played in with the Philadelphia Athletics. He started four games, going 1-2 with a 4.91 ERA, walking 12 batters. He pitched 18⅓ innings.