John William Salter (December 15, 1820 - August 2, 1869) was an English naturalist and palaeontologist.

Salter was apprenticed in 1835 to James De Carle Sowerby, and was engaged in drawing and engraving the plates for Sowerby's Mineral Conchology, the Supplement to his English Botany, and, other Natural History works. In 1842 he was employed for a short time by Adam Sedgwick in arranging the fossils in the Woodwardian Museum at Cambridge, and he accompanied the professor on several geological expeditions (1842-1845) into Wales. In 1846 he was appointed on the staff of the Geological Survey and worked under Edward Forbes until 1854; he was then appointed palaeontologist to the survey and gave his chief attention to the palaeozoic fossils, spending much time in Wales and the border counties. He contributed the palaeontological portion to Andrew Crombie Ramsay's Memoir on the Geology of North Wales (1866), assisted Roderick Murchison in his work on Siluria (1854 and later editions), and Sedgwick by preparing A Catalogue of the Collection of Cambrian and Silurian Fossils contained in the Geological Museum of the University of Cambridge (1873).

Salter prepared several of the Decades of the Geological Survey and became the leading authority on Trilobites, contributing to the Palaeontographical Society four parts of A Monograph of British Trilobites (1864-1867). He resigned his post on the Geological Survey in 1863.