William Lee (1739–1795) was an American diplomat during the Revolutionary War.
He was born at Stratford Hall Plantation in Westmoreland County, Virginia to Hon. Thomas Lee (1690–1750) and Hannah Harrison Ludwell (1701–1750). His brothers, all also active within the Continental Congress, were Arthur Lee (1740–1792), Francis Lightfoot Lee (1734–1797) and Richard Henry Lee (1732–1794).
Lee moved to London as a mercantile agent for Virginia in the tobacco trade and there married his heiress cousin Hannah Philippa Ludwell on March 7, 1769. After joining the Haberdashers Company he was appointed Sheriff of London for 1774 when Sheriff Plomer resigned. The other sheriff for that year, Stephen Sayes, was also American born. The position gave them the opportunity to press in high places the American case for less taxation and more representation. After his year as sheriff he was elected an Alderman and continued his campaign for American rights.
He served as an agent of the Continental Congress during the American Revolution, and was posted to Berlin and Vienna but forced by the political situation to take up residence in Frankfurt. He attempted, but failed, to obtain support from Austria or Prussia. An unofficial U.S.-Dutch treaty that he helped draft became the cause of the Fourth Anglo-Dutch War. Towards the end of the war he moved to Brussels, and then, leaving his wife and children there, returned to Virginia. His wife died suddenly in Ostend the following year on her way home with the children. Although ill and going blind, Lee in 1790 accepted the post of James City County sheriff in Virginia, serving two years.