William Mackenzie may refer to:
- William Mackenzie (ophthalmologist) (1791–1868), Scottish ophthalmologist
- William Mackenzie (contractor) (1794–1851), British civil engineering contractor
- William Lyon Mackenzie (1795–1861), Scottish-born journalist & rebel in Upper Canada; grandfather of Canadian prime minister William Lyon Mackenzie King
- William Mackenzie (railway entrepreneur) (1849–1923), railway contractor and entrepreneur in Canada, the United States, and Brazil
- William Douglas Mackenzie (1859–1936), American theologian
- William Mackenzie (publisher) (fl. 1870), Scottish publisher and printer
- William McKenzie, Baron McKenzie of Luton (born 1946), English politician
- William Mackenzie, 1st Baron Amulree (1860–1942), British barrister, public servant and politician
- William Alexander McKenzie (1874–1966), builder and political figure in British Columbia
- William Colin Mackenzie (1877–1938), Australian anatomist, benefactor, museum administrator and director
- William Forbes Mackenzie (1807–1862), Scottish Conservative politician and temperance reformer
- William Mackay Mackenzie (1871–1952), Scottish historian, archaeologist and writer
- William Mackenzie, 5th Earl of Seaforth (died 1740), Scottish nobleman
- Will McKenzie (Inbetweeners), fictional character
- Will Mackenzie (born 1938), American television director and actor
- Will MacKenzie (born 1974), American golfer
- Billy Mackenzie (1957–1997), singer
- Billy MacKenzie (motorcyclist) (born 1984), Scottish motocross racer
- Bill MacKenzie (1911–1990), Canadian ice hockey player
- Bill McKenzie (born 1949), Canadian ice hockey player
Famous quotes containing the word mackenzie:
“People sometimes tell me that they prefer barbarism to civilisation. I doubt if they have given it a long enough trial. Like the people of Alexandria, they are bored by civilisation; but all the evidence suggests that the boredom of barbarism is infinitely greater.”
—Kenneth MacKenzie Clark, Baron of Saltwood (1903–1983)