| Bill Karns | |
| Position: | Pitcher |
| Bats: | Left |
| Throws: | Left |
| Birth Date: | 28 December 1875 |
| Birth Place: | Richmond, Iowa |
| Death Place: | Seattle, Washington |
| Debutleague: | MLB |
| Debutdate: | August 1 |
| Debutteam: | Baltimore Orioles |
| Finalleague: | MLB |
| Finaldate: | September 26 |
| Finalteam: | Baltimore Orioles |
| Statleague: | MLB |
| Stat1label: | Win–loss record |
| Stat1value: | 1-0 |
| Stat2label: | Earned run average |
| Stat2value: | 6.35 |
| Stat3label: | Strikeouts |
| Stat3value: | 5 |
| Teams: | |
William Arthur Karns (December 28, 1875 – November 15, 1941) was a Major League Baseball pitcher. Karns played for the Baltimore Orioles in . In 3 career games, he had a 1–0 record, with a 6.35 ERA. He batted and threw left-handed.
Karns was born in Richmond, Iowa, and died in Seattle, Washington.