John Mackenzie may refer to:
John Mackenzie, 9th of Kintail (died 1561), chief of the Clan Mackenzie
John Mackenzie (banker) (1787–1854), Provost of Inverness
John Mackenzie (missionary) (1835-99), Scot who championed the rights of Africans in Southern Africa and proposed British intervention to curtail Boer influence
John Mackenzie (film director) (1928–2011), Scottish film director
John Ashton MacKenzie (born 1917), U.S. federal judge
John Mackenzie (sailor) (1876–1949), British Olympic sailor
John Mackenzie (VC) (1869–1915), Scottish recipient of the Victoria Cross
John MacKenzie (Medal of Honor) (1886–1933), American Medal of Honor recipient
John Joseph Mackenzie (1865–1922), Canadian pathologist
John Stuart Mackenzie (1860–1935), British philosopher
John Stuart MacKenzie, DO (born 1957), American physician
John Mackenzie, Lord MacLeod (1727–1789)
John Drew Mackenzie (died 1918), master craftsman and instructor of the Newlyn Copper school in Cornwall, UK
John MacKenzie (doctor) (died 1837), Scottish army surgeon and physician
John M. MacKenzie (born 1943), British historian of imperialism
John W. Mackenzie (died 1914), Canadian missionary to Vanuatu
John Mackenzie, 5th Earl of Cromartie, the current chief of Clan Mackenzie