Otto Martin Torell (1828 - 1900) was a Swedish naturalist and geologist. He was born in Varberg, Sweden on 5 June 1828. He was educated at Lund University for the medical profession, but became interested in zoological and geological studies, and being of independent means he devoted himself to science.
He gave his attention first especially to the invertebrate fauna and the physical changes of pleistocene and recent times. He studied the glacial phenomena of Switzerland, Spitsbergen and Greenland, making two Arctic expeditions in company with Adolf Erik Nordenskiöld. In 1866, he became professor of zoology and geology in the University of Lund, and in 1871 he was appointed chief of the Geological Survey of Sweden. In the latter capacity he labored until 1897. His published contributions, though of much interest and importance, were not large, but his influence in promoting a knowledge of geology in Sweden was of great service. His Arctic experiences enabled him to interpret the method of origin of the drift deposits in northern Europe, and to show that they were largely of glacial or fluvio-glacial origin. In the English drifts he recognized many boulders of Scandinavian origin. He died on 11 September 1900.
Publications include: Bidrag till Spitsbergens molluskfauna (1859); and memoirs to accompany several sheets of the Geological Survey map of Sweden.
He was elected a member of the Royal Swedish Academy of Sciences in 1870.