William Neill may refer to:

• William Neill (poet) (1922–2010), Scottish poet
• William Neill (rugby league) (1884–1964), Australian rugby league footballer of the early 20th century
• William Neill, birth name of Bud Neill (1911–1970), Scottish cartoonist of the mid 20th century
• William Neill (politician) (1889–1960), MP for Belfast North
• Bill Neill (born 1959), American football defensive lineman
• Billy Neill (1929–1997), Irish footballer
• Bill Neil (visual effects artist), American visual effects artist
• William Neill (priest) (born 1930), Archdeacon of Dromore

• Billy Neil (footballer, born 1939) (1939–2014), Scottish football centre-half who represented Great Britain at the 1960 Olympics
• Billy Neil (footballer, born 1944), Scottish football winger for Millwall
• William Neal (disambiguation)
• William Neale (disambiguation)
• William Neile (1637–1670), English mathematician
• Will E. Neal (1875–1959), physician and politician
• William Neel (died 1418), MP
• Willie Neil (fl. 1920s), Scottish footballer with Airdrieonians
• William O'Neill (disambiguation)