William Byrne
William, Bill or Billy Byrne may refer to:
- William Byrne, former boxer from New Zealand
- William Byrne , Irish missionary and educator
- William Byrne , British artist
- William Byrne , American painter
- William Byrne, Irish priest
- William A. Byrne, Irish poet and educator
- William D. Byrne Jr., United States Navy admiral
- William Draper Byrne, Roman Catholic bishop of Springfield, Massachusetts, United States
- William Henry Byrne, Irish architect
- William Matthew Byrne Sr., American judge
- William Matthew Byrne Jr., American judge, and son of William Matthew Byrne Sr
- William Michael Byrne, Irish revolutionary
- William Patrick Byrne, member of the British Civil Service
- William Pitt Byrne, British newspaper editor and proprietor of The Morning Post
- William T. Byrne, American politician in New York
- Bill Byrne , American football player
- Bill Byrne, American collegiate athletic director
- Bill Byrne , Australian footballer for Fitzroy
- Bill Byrne , Australian footballer for Melbourne
- Bill Byrne , Member of the Queensland Parliament
- Bill Byrne , founder of the first women's professional basketball league
- Billy Byrne , English footballer
- Billy Byrne , Irish retired hurler