William Clarke Wontner (17 January 1857 Stockwell, Surrey - 23 September 1930 Worcester), was an English portrait painter steeped in Academic Classicism and Romantic.
Wontner was born in Stockwell, Surrey, the son of noted architect, designer and renderer William Hoff Wontner (1814–1881) and Catherine Smith.
Under the tutelage of his father, Wontner worked with John William Godward (1861–1922), a noted exponent of what became known as Greco-Roman style. The two were destined to become great friends.
Wontner was a relatively minor painter who was part of the neo-classical movement in England, led by Alma-Tadema. His style favoured seductively languorous women against classical or oriental marbled backdrops. His faithfully rendered fabrics draped over patently European models, somehow created an air of Orientalism. His work was exhibited at the Royal Academy from 1879, at the Society of British Artists and at the Royal Institute of Painters in Water Colours. When the Grosvenor Gallery closed in 1890, Wontner exhibited at the New Gallery.
Wontner married Jessie Marguerite Keene (1872–1950), daughter of Charles Joseph Keene, on 7 June 1894 at St. Dominic's Priory Church, Naverstock Hill in Hampstead. The couple had no children. Wontner was buried on 26 September 1930 at Ripple in Worcestershire.