John Willis Clark (1833 – 1910), sometimes J. W. Clark, was an English academic and antiquarian.
Clark was born into a Cambridge University academic family, and was a nephew of Prof. Robert Willis. Educated at Eton and Trinity College, Cambridge, he spent his life at the university, serving as Fellow of Trinity, Superintendent of the Cambridge University Museum of Zoology from 1866-1892, and Registrary of the University. He was also Secretary of the Cambridge Antiquarian Society. He is buried in the Mill Road cemetery, Cambridge.