Thomas Erskine, 9th Earl of Kellie (about 1746 – 6 February 1828) was a Scottish merchant, landowner and politician who for many years lived in the Swedish port city of Gothenburg. He returned to Scotland in 1799 when he inherited an earldom from his nephew Charles Erskine, 8th Earl Kellie, and thus, became the 9th Earl of Kellie.
Erskine was born in Scotland to an family that had become comparatively impoverished because of confiscations due to their support for the Stuart pretenders. He was probably born at Cambo House in Fife, one of the forfeited properties.
At a young age, he was sent to Gothenburg to learn a trade. He was employed in 1759 in the office of George Carnegie, a Jacobite exile who had established himself as a merchant there. After a few years, he transferred to the firm of the iron-exporting English brothers John and Benjamin Hall, and became a partner in the firm in 1767. In his 30 years as a partner, he managed to amass a large fortune. In addition to retaining his partnership in the firm of the Hall brothers, Erskine pursued business under his own name, later partnering with David Mitchell from Montrose, who took over Thomas Erskine & Co. as sole owner after Erskine's departure for Scotland.
In 1775 Erskine was appointed British consul for Gothenburg, Marstrand, and the other port cities on the West Coast of Sweden. As such, he wrote regular reports to the British government, including reports on the Swedish contraband trade with France during the revolutionary wars. This position also enhanced his social position in Gothenburg. He was one of the 20 (at the time unmarried and for the largest part British-born) founding members of the Bachelors' Club, an English-type gentlemen's club established in 1769 mainly in order to circumvent a ban on the playing of billiards at public establishments.