Henry Alleyne Nicholson was born on September 11, 1844, in Penrith, Cumberland, England.

He was a British paleontologist and zoologist. He was educated at Appleby Grammar School and then studied sciences at the universities of Göttingen (Ph.D., 1866) and Edinburgh (D.Sc., 1867; M.D., 1869). In 1869, he became a lecturer in natural history at the extra-mural classes linked to the University of Edinburgh. In 1871, he was appointed professor of natural history at the University of Toronto, Ontario; in 1874, professor of biology at the Durham College of Science, Ontario, and in 1875, professor of natural history at the University of St. Andrews, Scotland. This last post he held until 1882 when he became Regius Professor of natural history at the University of Aberdeen. His original work was mainly on fossil invertebrates (graptolites, stromatoporoids, and corals), but he also did much fieldwork, especially in England’s Lake District. In 1870, he was elected a Fellow of the Royal Society of Edinburgh and in 1897, a Fellow of the Royal Society of London. He was awarded the Lyell Medal by the Geological Society in 1888.

In 1867, he married Isabella Hutchison. He died on January 19, 1899, in Aberdeen, Aberdeenshire, Scotland.