Günther Oskar Dyhrenfurth (November 12, 1886 – April 14, 1975) was a German-born, German and Swiss mountaineer, geologist and Himalayan explorer. He led the International Himalaya Expedition (IHE) 1930 to Kangchenjunga, and another one, IHE 1934, to the Baltoro-region in the Karakorams, especially to explore the Gasherbrum-Group. This expedition made the first ascent of Sia Kangri and some of its sub-peaks and provided detailed information about the accessibility of the 8000ers Gasherbrum I and II. The first ascent of Gasherbrum I in 1958 was accomplished via the route proposed by Dyhrenfurth following the so-called IHE-spur and the SE-ridge.