William Hay
William, Will, Willie, or Bill Hay may refer to:
Arts and entertainment
- William Hay (architect), Scottish architect
- William Delisle Hay, British author
- William Hay (author), Australian novelist and essayist
- Bill Hay (radio announcer), American radio announcer
- Will Hay, English comedian and actor
Law and politics
- William Hay (died 1664), English politician
- William Hay (Seaford MP), British MP for Seaford
- William Robert Hay, British barrister, cleric and magistrate
- William Hay (Australian politician)
- Willie Hay, Baron Hay of Ballyore, Northern Irish peer and Assemblyman
Nobility
- William Hay, 1st Earl of Erroll, Scottish peer
- William Hay, 3rd Earl of Erroll, Scottish peer
- William Hay, 4th Earl of Erroll, Scottish peer and soldier
- William Hay, 5th Earl of Erroll, Scottish peer and statesman
- William Hay, 6th Earl of Erroll, Scottish peer
- William Hay, 6th Lord Hay of Yester, Scottish nobleman and courtier
- William Hay, 10th Earl of Erroll, Scottish nobleman
- William Hay, 4th Earl of Kinnoull, Scottish peer
- William Hay, 6th Earl of Kinnoull, Scottish peer
- William Hay, 17th Earl of Erroll, Scottish peer
- William Hay, 18th Earl of Erroll, Scottish peer
- William Hay, 19th Earl of Erroll, Scottish peer
- William Hay, 10th Marquess of Tweeddale, British politician, MP for Taunton and Haddington
- William Hay, 11th Marquess of Tweeddale, Scottish aristocrat, land owner and soldier
- William Hay, 15th Earl of Kinnoull, Scottish peer, surveyor and farmer
Science and medicine
- William Howard Hay, American doctor, author, lecturer and dietician
- William Perry Hay, American zoologist
- William Walter Hay, American civil engineer and professor of railway engineering
- William W. Hay, American geologist and paleoclimatologist
Sports
- William Hay (English cricketer), English cricketer
- William Arthur Hay, Australian cricketer
- Bill Hay (footballer), Australian footballer
- Bill Hay (field hockey), Singaporean Olympic hockey player
- Bill Hay, Canadian ice hockey player
- Billy Hay (bowls), Scottish lawn bowler
Others
- William Hay (bishop), Scottish bishop
- William Hay (police commissioner), English police commissioner
- William H. Hay, United States Army officer
- Rupert Hay, British Indian Army officer and administrator