Thomas Fairfax, 6th Lord Fairfax of Cameron (22 October 1693 – 9 December 1781) was a Scottish peer.
He was the son of Thomas Fairfax, 5th Lord Fairfax of Cameron and of Catherine, daughter of Thomas Colepeper, 2nd Baron Colepeper.
The only resident peer in late colonial America, Fairfax administered his vast Northern Neck Proprietary — a Virginia land grant dating back to 1649 — from his wilderness estate at Greenway Court, Virginia.
Various place names in Northern Virginia and the Eastern Panhandle of West Virginia are named for him—most notably Fairfax County, Virginia and the independent City of Fairfax, Virginia.