Alexander Mackenzie most commonly refers to:
Alexander Mackenzie or MacKenzie may also refer to:
- Alexander Mackenzie of Kintail (died after 1471), Scottish clan chief
- Alexander Muir Mackenzie (1764–1835), Scottish advocate and landowner
- Alexander Slidell Mackenzie (1803–1848), US Navy officer involved in the "Somers Affair"
- Alexander Mackenzie (historian) (1838–1898), Scottish historian
- Alexander Slidell MacKenzie (1842–1867), US Navy officer, son of Alexander Slidell Mackenzie
- Alexander Mackenzie (civil servant) (1842–1902), British colonial official in Burma
- Alexander Mackenzie (engineer) (1844–1921), US Army Chief of Engineers
- Alexander Mackenzie (composer) (1847–1935), Scottish violinist, conductor, composer and head of the Royal Academy of Music in London
- Alexander Marshall Mackenzie (1848–1933), Scottish architect
- Alick Mackenzie or Alexander Cecil Knox Mackenzie (1870–1947), Australian cricketer
- Alexander MacKenzie (priest) (1876–1969), Provost of St Andrew's Cathedral, Inverness
- Alexander George Robertson Mackenzie (1879–1963), Scottish architect and son of Alexander Marshall Mackenzie
- Alex Mackenzie (1885–1965), Scottish character actor
- Alexander Mackenzie (artist) (1923–2002), St Ives school artist
- Alexander Mackenzie (Australian politician) (born 1941)
- Alexander MacKenzie (rugby union) (born 1956), Scottish rugby player