| John Thornton | |
| Position: | Pitcher |
| Birth Date: | 22 May 1869 |
| Birth Place: | Washington, D.C. |
| Death Place: | Washington, D.C. |
| Bats: | Left |
| Throws: | Right |
| Debutleague: | MLB |
| Debutdate: | August 14 |
| Debutyear: | 1889 |
| Debutteam: | Washington Nationals |
| Finalleague: | MLB |
| Finaldate: | September 15 |
| Finalyear: | 1892 |
| Finalteam: | St. Louis Browns |
| Statleague: | MLB |
| Stat1label: | Win–loss record |
| Stat1value: | 15–19 |
| Stat2label: | Earned run average |
| Stat2value: | 4.10 |
| Stat3label: | Strikeouts |
| Stat3value: | 57 |
| Teams: |
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John James Thornton (May 22, 1869 – April 26, 1935) was a Major League Baseball pitcher for the Washington Nationals (1889) and Philadelphia Phillies (1891–1892). He also played outfield for the St. Louis Browns (1892). He continued to play in the minor leagues through 1899. He managed in the minors in 1906.