William Douglas
William Douglas is the name of the following people:
- William Douglas of Douglas († 1213) , Scottish nobleman
- William Douglas of Douglas († 1274) (around 1220 - around 1274), Scottish nobleman
- William Douglas of Douglas († 1298) (around 1240–1299), Scottish nobleman
- William Douglas of Douglas († 1333) , Scottish nobleman
- William Douglas, Lord of Liddesdale (around 1310–1353), Scottish nobleman and military man
- William Douglas, 1st Earl of Douglas (around 1327–1384), Scottish nobleman
- William Douglas of Nithsdale († 1392), Scottish knight
- William Douglas, 2nd Earl of Angus (around 1398–1437), Scottish nobleman
- William Douglas, 6th Earl of Douglas (around 1424–1440), Scottish nobleman
- William Douglas, 8th Earl of Douglas (1425-1452), Scottish nobleman
- William Douglas, 9th Earl of Angus (1532–1591), Scottish nobleman
- William Douglas, 6th Earl of Morton (1540-1606), Scottish nobleman
- William Douglas, 10th Earl of Angus (1552-1611), Scottish nobleman
- William Douglas, 7th Earl of Morton (1582–1648), Lord High Treasurer of Scotland
- William Douglas, 1st Marquess of Douglas (1589–1660), Scottish nobleman
- William Douglas, 11th Earl of Angus (1590–1660), Scottish nobleman
- William Douglas-Hamilton, Duke of Hamilton (1634–1694), Scottish peer
- William Douglas, 1st Duke of Queensberry (1637–1695), Scottish nobleman and government official
- William Douglas, 1st Baronet (of Glenbervie) († around 1660), Scottish nobleman
- William Douglas, 1st Baronet (of Castle Douglas) († 1809), Scottish nobleman
- William Douglas, 4th Duke of Queensberry (1725-1810), Scottish nobleman
- William Sholto Douglas, 1st Baron Douglas of Kirtleside (1893–1969), British Marshal of the Royal Air Force
- William Douglas (Barbados) (1921–2003), Governor General of Barbados
- William Douglas-Hamilton, Duke of Hamilton (1634–1694), Scottish nobleman
- William H. Douglas (1853–1944), American politician
- William Lewis Douglas (1845-1924), American politician (Massachusetts)
- William O. Douglas (1898–1980), American lawyer and judge