| Billy Orr | |
| Position: | Shortstop |
| Bats: | Right |
| Throws: | Right |
| Birth Date: | April 22, 1891 |
| Birth Place: | San Francisco, California, US |
| Death Place: | St. Helena, California, US |
| Debutleague: | MLB |
| Debutdate: | May 3 |
| Debutteam: | Philadelphia Athletics |
| Finalleague: | MLB |
| Finaldate: | May 22 |
| Finalteam: | Philadelphia Athletics |
| Statleague: | MLB |
| Stat1label: | Batting average |
| Stat1value: | .187 |
| Stat2label: | Home runs |
| Stat2value: | 0 |
| Stat3label: | Runs batted in |
| Stat3value: | 8 |
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William John Orr (April 22, 1891 – March 10, 1967) was a Major League Baseball infielder. He played parts of two seasons in the majors, and, for the Philadelphia Athletics. He played primarily at shortstop, but also played all three other infield positions.
After his major league career, Orr played for ten years in the Pacific Coast League. He also briefly served as head coach of the Stanford Cardinal baseball program, and managed the Salt Lake City Bees in .