Sidney Richard Percy was an English landscape painter during the Victorian era, and a member of the Williams family of painters.

Sidney Richard Percy was born Sidney Richard Percy Williams on 22 March 1822 in London. He was the fifth son of the painter Edward Williams (1781–1855) and Ann Hildebrandt (c.1780-1851), and a member of the Williams family of painters, who were related to such famous artists as James Ward, R.A. and George Morland.