Sir Thomas Mackenzie (1853–1930) was Prime Minister of New Zealand in 1912, and later High Commissioner.
Thomas Mackenzie may also refer to:
- Thomas MacKenzie (Russian admiral) (1740–1786), rear admiral, founder of Sevastopol
- Thomas Mackenzie (Royal Navy officer) (1753–1813), Royal Navy admiral
- Thomas Mackenzie (Scottish politician) (1793–1856), MP for Ross and Cromarty, 1837–1847
- Thomas Mackenzie, Lord Mackenzie (1807–1869), Scottish judge
- Thomas Mackenzie (Australian politician) (1854–1934), member of the New South Wales Legislative Assembly
- Thomas Mackenzie (illustrator) (1887–1944), illustrator
- Tom MacKenzie (1882–1927), Australian rules footballer
- Thomas Mackenzie (1789–1822), Member of parliament for Ross-shire, 1818–1822