Sir Ernest Henry Shackleton (15 February 1874 – 5 January 1922) was a polar explorer.

Shackleton led three British expeditions to the Antarctic. He was one of the principal figures of the "Heroic Age of Antarctic Exploration". The Shackletons were originally from Yorkshire, but Shackleton was born in County Kildare, Ireland. Shackleton and his Anglo-Irish family moved to Sydenham in suburban London when he was ten.

His first experience of the polar regions was as third officer on Captain Robert Falcon Scott's Discovery Expedition, 1901–04, from which he was sent home early on health grounds. Determined to do better, he returned to Antarctica in 1907 as leader of the Nimrod Expedition. In January 1909, he and three companions made a southern march. They went to the farthest South latitude anyone had reached, at 88° 23' S, 97 geographical miles (112 statute miles, 180 km) from the South Pole. This was by far the closest to the pole in exploration history up to that time. For this achievement, Shackleton was knighted by Edward VII on his return home.