William Sykes
William or Bill Sykes may refer to:
- Bill Sykes, Member for Benalla in the Victorian Parliament
- Bill Sykes (priest), English chaplain and author
- William Sykes (convict), convict transported to Western Australia
- William Sykes (priest), Anglican clergyman
- William Sykes (businessman), English manufacturer of sporting goods
- William Henry Sykes, Indian Army officer
- William Sykes (cricketer), English clergyman and cricketer
- William Robert Sykes, British engineer from London
- William Stanley Sykes, British anaesthetist and crime writer
- Charles Henry Sykes, known as Bill, American cartoonist