| Bill O'Hara | |
| Position: | Center fielder |
| Birth Date: | 14 August 1883 |
| Birth Place: | Toronto, Ontario, Canada |
| Death Place: | Jersey City, New Jersey |
| Bats: | Left |
| Throws: | Right |
| Debutleague: | MLB |
| Debutdate: | April 15 |
| Debutyear: | 1909 |
| Debutteam: | New York Giants |
| Finalleague: | MLB |
| Finaldate: | May 8 |
| Finalyear: | 1910 |
| Finalteam: | St. Louis Cardinals |
| Statleague: | MLB |
| Stat1label: | Batting average |
| Stat1value: | .232 |
| Stat2label: | Home runs |
| Stat2value: | 1 |
| Stat3label: | Runs batted in |
| Stat3value: | 32 |
| Teams: |
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William Alexander O'Hara (1883–1931) was a Major League Baseball outfielder. He started his professional baseball career in 1902 and played for the Baltimore Orioles from 1905 to 1908. He then played in the National League for the New York Giants and St. Louis Cardinals before finishing his career with the Toronto Maple Leafs.