| Harry O'Neill | |
| Position: | Pitcher |
| Bats: | Right |
| Throws: | Right |
| Birth Date: | November 20, 1892 |
| Birth Place: | Lindsay, Ontario |
| Death Place: | Ridgetown, Ontario |
| Debutleague: | MLB |
| Debutdate: | September 15 |
| Debutteam: | Philadelphia Athletics |
| Finalleague: | MLB |
| Finaldate: | May 28 |
| Finalteam: | Philadelphia Athletics |
| Statleague: | MLB |
| Stat1label: | Win–loss record |
| Stat1value: | 0–0 |
| Stat2label: | Strikeouts |
| Stat2value: | 2 |
| Stat3label: | Earned run average |
| Stat3value: | 1.80 |
| Teams: |
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Joseph Henry O'Neill was a Major League Baseball pitcher. He pitched in four games for the Philadelphia Athletics over two seasons, one in and three in .
After his playing career ended, O'Neill spent two seasons as a minor league baseball manager. He managed the Salt Lake City Bees in and the Boise Senators in .