Thomas Barclay (1728 – January 19, 1793) was a Philadelphia merchant, America's first consul in France (1781–1787) and the American diplomat who negotiated United States America's first treaty with the sultan of Morocco in 1786. He was the first American diplomat to die in a foreign country in the service of the United States. In 1770 Thomas Barclay married Mary Hoops in Philadelphia. Born in 1750 in western Pennsylvania, Mary had moved to Philadelphia with her family at the age of eleven. She was one of eight children of Adam Hoops (1708–1771) and Elizabeth Finney Hoops (1720–1782).