| Billy Campbell | |
| Position: | Pitcher |
| Bats: | Left |
| Throws: | Left |
| Birth Date: | 5 November 1873 |
| Birth Place: | Pittsburgh, Pennsylvania, U.S. |
| Death Place: | Cincinnati, Ohio, U.S. |
| Debutleague: | MLB |
| Debutdate: | April 17 |
| Debutyear: | 1905 |
| Debutteam: | St. Louis Cardinals |
| Finalleague: | MLB |
| Finaldate: | August 23 |
| Finalyear: | 1909 |
| Finalteam: | Cincinnati Reds |
| Statleague: | MLB |
| Stat1label: | Win–loss record |
| Stat1value: | 23–25 |
| Stat2label: | Earned run average |
| Stat2value: | 2.80 |
| Stat3label: | Strikeouts |
| Stat3value: | 116 |
| Teams: | |
William James Campbell (November 5, 1873 – October 6, 1957) was an American professional baseball player. He was a left-handed pitcher over parts of four seasons (1905, 1907–09) with the St. Louis Cardinals and Cincinnati Reds. For his career, he compiled a 23–25 record, with a 2.80 earned run average, and 116 strikeouts in 407⅔ innings pitched.
He was born in Pittsburgh, Pennsylvania and later died in Cincinnati, Ohio at the age of 83.