Thomas Lowndes (January 22, 1766 – July 8, 1843) was an American planter, lawyer and politician from Charleston, South Carolina. He was the son of Rawlins Lowndes, governor of South Carolina during the American Revolutionary War and half-brother of William Lowndes (congressman), who helped secure the declaration of the War of 1812. Educated in Charleston, he studied law there and became a practicing lawyer in the city in the late 18th century. He was a member of the state legislature from 1792 to 1799. He represented South Carolina's 1st Congressional District in the U.S. Congress from March 4, 1801, to March 3, 1805. He was not re-elected in 1804. He failed to win back his seat in 1808, and retired from public life thereafter. He died in Charleston on July 8, 1843.

Thomas Lowndes
Portrait by Gilbert Stuart
Member of the U.S. House of Representatives from South Carolina's 1st district
In office March 4, 1801 – March 3, 1805
Preceded by	Thomas Pinckney
Succeeded by	Robert Marion
Member of the South Carolina House of Representatives from St. Philip's and St. Michael's Parish
In office November 26, 1792 – December 21, 1799
Personal details
Born	(1766-01-22)January 22, 1766 Charleseton, Province of South Carolina, British America
Died	July 8, 1843(1843-07-08) (aged 77) Charleston, South Carolina, U.S.
Political party	Federalist