William Lewin (1747 - 1795) was an English naturalist and illustrator.
Lewin grew up in Stepney, the son of a rate mariner. In 1776 he was earning a living as a pattern drawer, and by 1783 was describing himself as a painter, and he specialised in natural history subjects.
In 1789 he began to issue his The Birds of Great Britain, with Their Eggs, Accurately Figured, which he had been working on for the previous twenty years. It included 323 watercolours, 271 of birds and 52 of eggs, which he painted himself for the sixty copies which were published. In 1793 he began to issue a second addition, for which Lewin produced etched copper plates of the illustrations. Lewin produced the first 103 plates, plates 104-336 were done by his three sons: Thomas, Thomas William and John William.
In 1791 his friend John Latham sponsored Lewin's membership of the Linnean Society.
Lewin was buried at Edmonton on December 10, 1795.
