William, Will, Willie, or Bill Hay may refer to:
Arts and entertainment William Hay (architect) (1818–1888), Scottish architect William Delisle Hay (born 1853), British author William Hay (author) (1875–1945), Australian novelist and essayist Bill Hay (radio announcer) (1887–1978), American radio announcer Will Hay (1888–1949), English comedian and actor
Law and politics William Hay (died 1664) (1594–1664), English politician William Hay (Seaford MP) (1695–1755), British MP for Seaford William Robert Hay (1761–1839), British barrister, cleric and magistrate William Hay (Australian politician) (1816–1908) Willie Hay, Baron Hay of Ballyore (born 1950), Northern Irish peer and Assemblyman
Nobility William Hay, 1st Earl of Erroll (1423–1462), Scottish peer William Hay, 3rd Earl of Erroll (1449–1507), Scottish peer William Hay, 4th Earl of Erroll (1449–1513), Scottish peer and soldier William Hay, 5th Earl of Erroll (1495–1522), Scottish peer and statesman William Hay, 6th Earl of Erroll (1521–1541), Scottish peer William Hay, 6th Lord Hay of Yester (died 1591), Scottish nobleman and courtier William Hay, 10th Earl of Erroll (1590s–1636), Scottish nobleman William Hay, 4th Earl of Kinnoull (died 1677), Scottish peer William Hay, 6th Earl of Kinnoull (died 1709), Scottish peer William Hay, 17th Earl of Erroll (1772–1819), Scottish peer William Hay, 18th Earl of Erroll (1801–1846), Scottish peer William Hay, 19th Earl of Erroll (1823–1891), Scottish peer William Hay, 10th Marquess of Tweeddale (1826–1911), British politician, MP for Taunton and Haddington William Hay, 11th Marquess of Tweeddale (1884–1967), Scottish aristocrat, land owner and soldier William Hay, 15th Earl of Kinnoull (1935–2013), Scottish peer, surveyor and farmer
Science and medicine William Howard Hay (1866–1940), American doctor, author, lecturer and dietician William Perry Hay (1872–1947), American zoologist William Walter Hay (1908–1998), American civil engineer and professor of railway engineering William W. Hay (1934–2022), American geologist and paleoclimatologist
Sports William Hay (English cricketer) (1849–1925), English cricketer Arthur Hay (cricketer) (William Arthur Hay, 1873–1945), Australian Methodist minister and cricketer Bill Hay (footballer) (1934–2018), Australian footballer Bill Hay (field hockey) (born 1934), Singaporean Olympic hockey player Bill Hay (born 1935), Canadian ice hockey player Billy Hay (bowls) (1963–2015), Scottish lawn bowler
Others William Hay (bishop) (1647–1707), Scottish bishop William Hay (police commissioner) (1794–1855), English police commissioner William H. Hay (1860–1946), United States Army officer Rupert Hay (William Rupert Hay, 1893–1962), British Indian Army officer and administrator
See also William Haye (1948–2019), Jamaican cricketer William Hay Macnaghten (1793–1841), Anglo-Indian civil servant William Hays (disambiguation) William Hayes (disambiguation)