Robert Troup (August 19, 1756 – January 14, 1832) was an American soldier, lawyer and jurist.
Born in Elizabethtown, New Jersey, Troup attended King's College (now Columbia University). At King's he was the roommate of Alexander Hamilton and read law under John Jay.
At the start of the American Revolutionary War, Robert Troup joined the Continental Army, serving from 1776 to 1780 and obtaining the rank of lieutenant colonel. Serving under General Nathaniel Woodhull he was captured by the British near Brooklyn during the Battle of Long Island on August 27, 1776 and confined to the Jersey Prison Ship. He was later transferred to the Provost prison until he was exchanged in 1777. He was an aide to General Horatio Gates and participated in the surrender of General Burgoyne at the Battle of Saratoga on October 17, 1777. He is depicted in the painting of the Surrender of General Burgoyne at Saratoga by John Trumbull.
Troup was appointed by Congress as Secretary of the Board of War in 1778 and Secretary of the Board of Treasury from 1779 to 1780. He maintained a private law practice in Albany, New York from 1782 to 1783, and in New York City from 1784 to 1796. He was a member of the New York State Assembly in 1786. From 1789 to 1796, he served as Clerk of Court of the District of New York until he was nominated by President George Washington, on December 9, 1796, to fill the judicial seat vacated by John Laurance. Confirmed by the United States Senate on December 10, 1796, Troup received his commission the same day and served as a Judge in the District of New York until his resignation on April 4, 1798. He then returned to private practice in New York City.