William Sinclair may refer to:
- William Sinclair (footballer) (born 1934), Scottish professional footballer
- William Sinclair (bishop) (died 1337), bishop of Dunkeld
- William Sinclair, 1st Earl of Caithness (1410–1484), Scottish nobleman
- William Sinclair, 2nd Earl of Caithness (1459–1513), Scottish nobleman
- William Sinclair (father) (1804–1878), Scottish author and rector of Pulborough, Sussex
- William Pirrie Sinclair (1837–1900), MP for Antrim and Falkirk Burghs
- William Sinclair (son) (1850–1917), Anglican priest and author
- W. E. N. Sinclair (1873–1947), Canadian barrister, solicitor and politician
- William Sinclair (fur trader), chief factor of the Hudson's Bay Company
- William H. Sinclair, president of the Galveston street car company
- Will Sinclair, character in Angel in My Pocket
Famous quotes containing the word sinclair:
“An involuntary return to the point of departure is, without doubt, the most disturbing of all journeys.”
—Iain Sinclair (b. 1943)