| Bill Malarkey | |
| Position: | Pitcher |
| Bats: | Right |
| Throws: | Right |
| Birth Date: | 26 November 1878 |
| Birth Place: | Port Byron, Illinois |
| Death Place: | Phoenix, Arizona |
| Debutleague: | MLB |
| Debutdate: | April 16 |
| Debutyear: | 1908 |
| Debutteam: | New York Giants |
| Finalleague: | MLB |
| Finaldate: | August 16 |
| Finalyear: | 1908 |
| Finalteam: | New York Giants |
| Statleague: | MLB |
| Stat1label: | Win–loss record |
| Stat1value: | 0-2 |
| Stat2label: | Earned run average |
| Stat2value: | 2.57 |
| Stat3label: | Strikeouts |
| Stat3value: | 12 |
| Teams: | |
William John Malarkey (November 26, 1878 – December 12, 1956) was a pitcher in Major League Baseball.
Malarkey's only season in the majors was 1908, when he pitched 35 innings for the New York Giants. He played in the minor leagues until 1915, winning a career-high 25 games in 1913.