Ernst Reiss (24 February 1920, Davos – 3 August 2010, Basel) was a Swiss mountaineer, who together with Fritz Luchsinger was the first to climb the fourth highest mountain on earth in 1956.On 18 May 1956, Reiss and Luchsinger successfully climbed the 8516 meter-high Lhotse, the fourth highest mountain on earth. Lhotse is connected to Mount Everest via the South Col on the border of Tibet and Nepal.Reiss was a member of the 1956 Swiss Everest–Lhotse expedition.