Lieutenant-Colonel Robert Fulke Greville FRS MP (3 February 1751 – 27 April 1824) was a British Member of Parliament (MP) and courtier.
The son of Francis Greville, 1st Earl of Warwick and Elizabeth Hamilton, and brother to Charles Francis Greville, he was educated at Edinburgh University. He was commissioned as a cornet in the 10th Dragoons in 1768, and promoted to lieutenant in 1772; he became a captain in the 1st Foot Guards in 1775 and lieutenant-colonel in 1777.
He was Member of Parliament for Warwick from 1774 to 1780, supporting the Tory government of Lord North, and for New Windsor from 1796 to 1806.
Greville served as Equerry to King George III from 1781 to 1797 and Groom of the Bedchamber from 1800 to 1818 (from 1812 at Windsor). His diaries give remarkable insight into the King's illness and recovery from porphyria. They also record the King's 1794 season at Weymouth in considerable detail. He hence appears as a character in the play The Madness of George III and its film adaptation, played in the latter by Rupert Graves.