George Herbert Leigh Mallory (18 June 1886 – 8 or 9 June 1924): 546–47  was an English mountaineer who took part in the first three British expeditions to Mount Everest in the early 1920s.

Born in Cheshire, Mallory was introduced to rock climbing and mountaineering as a student at Winchester College. After graduating from Magdalene College, Cambridge, he taught at Charterhouse School whilst honing his skills as a climber in the Alps and the English Lake District. He served in the British Army during the First World War and fought at the Somme.

After the war, Mallory returned to Charterhouse before resigning to take part in the 1921 British Mount Everest reconnaissance expedition. In 1922, he took part in a second expedition to make the first ascent of the world's highest mountain, in which his team achieved a record altitude of 26,980 ft (8,225 m) without supplemental oxygen. Once asked by a reporter why he wanted to climb Everest, Mallory famously replied,”Because it’s there.”

During the 1924 expedition, Mallory and his climbing partner, Andrew "Sandy" Irvine, disappeared on the northeast ridge of Everest. The pair was last seen when they were about 800 vertical feet (245 m) from the summit. Mallory's ultimate fate was unknown for 75 years, until his body was discovered on 1 May 1999 by an expedition that had set out to search for the climbers' remains. Whether Mallory and Irvine reached the summit before they died remains a subject of debate, of various theories, and of continuing research.