Lieutenant General Sir Manley Power, KCB, ComTE (1773 – 7 July 1826) was a British military leader who fought in a number of campaigns for Britain and rose to the rank of Lieutenant General. He is chiefly remembered for leading a brigade of Portuguese troops under The Duke of Wellington in the Iberian Peninsular War. He is also remembered for jointly causing the removal of Sir George Prevost, governor-in-chief of British North America, for Prevost's refusal to press the attack on Plattsburgh, New York, in 1814, during the War of 1812. After his active military service Sir Manley Power was appointed Lieutenant Governor of Malta.
His grandfather, Sir Henry Power, was a captain of the Battle-Axe Guards. His father, Captain Lieutenant Bolton Power, served in the 20th Regiment of Foot and fought in all battles of the Seven Years' War, and later in the American Revolutionary War under Guy Carleton and John Burgoyne. Manley Power followed in his forefather's footsteps and was a career soldier, starting as an ensign in his father's old regiment, the 20th Regiment of Foot, on 27 August 1783, when he was either 9 or 10 years old. He served in Halifax, Nova Scotia (1795–97), Holland (1799), and Minorca (1800). He was part of the force under the command of Sir Ralph Abercromby at the Battle of Alexandria (1801), and later served with the Royal Horse Guards (1803–05). After rising to Lieutenant Colonel of the 32nd Regiment of Foot, he entered the Peninsular War and was attached to the Portuguese army under the command of Sir William Beresford and was promoted to lieutenant general in 1813.