Thomas Pitt, 1st Earl of Londonderry

Thomas Innes Pitt, 1st Earl of Londonderry (c. 1688 – 12 September 1729) was a British politician. He served as Governor of the Leeward Islands from 1728 to 1729.

Pitt was the second son of Thomas Pitt, of Boconnoc, and his wife Jane Innes, daughter of James Innes. William Pitt the Elder was his nephew and William Pitt the Younger his great-nephew. Pitt sat as a Member of Parliament for Wilton from 1713 to 1727 and for Old Sarum from 1727 to 1728. The latter year he was appointed Governor of the Leeward Islands, a post he held until his death the following year. Pitt was also a Colonel in the Princess of Wales's Own Regiment of Horse and in the Prince George of Denmark's Regiment.

Pitt married Lady Frances Ridgeway, daughter of Robert Ridgeway, 4th Earl of Londonderry, on 10 March 1717. They had two sons and one daughter. The earldom of Londonderry held by his father-in-law had become extinct on the latter's death in 1714. In 1719 the Londonderry title was revived for Pitt who was created Baron Londonderry in the Peerage of Ireland. Seven years later the earldom was also revived when he was created Viscount Gallen-Ridgeway and Earl of Londonderry, again in the Peerage of Ireland. Lord Londonderry died on 12 September 1729, and was succeeded in his peerages by his eldest son Thomas Pitt.