William Kirby
William Kirby may refer to:
- William Kirby (entomologist), English entomologist
- William Kirby (author), Canadian author
- William C. Kirby, professor at Harvard University
- William F. Kirby, American politician
- William Forsell Kirby, English entomologist & folklorist
- William T. Kirby, businessman
- William Kirby (Gaelic footballer), Gaelic footballer
- William Kirby (footballer, born 1883), English footballer
- William Kirby (cricketer), English cricketer
- Bill Kirby, Australian swimmer
- Cam Kirby or William J. Cameron Kirby, Canadian politician