William Charles Piguenit was an Australian landscape painter.
Piguenit was born in Hobart, Tasmania, to Frederick Le Geyt Piguenit and Mary Ann née Igglesden. Frederick had been transported to Van Diemen's Land in 1830, with Mary Ann following him. They married in Hobart in 1833. His first artistic influences came from his mother, who set up a school for young ladies where she taught "French, music and drawing".

In 1850 he became a draftsman with the Tasmanian Lands & Survey Department, working in particular on the Geological Survey of Tasmania. During this employment Piguenit provided lithographic illustrations for The Salmon Ponds and vicinity, New Norfolk, Tasmania. He took painting lessons from Scottish immigrant artist Frank C. Dunnett (1822-1891). Until he got a good price for a painting from Sir James Agnew, the Premier of Tasmania, he had little success as a painter. Piguenit left public service in 1873 to devote his time to painting. His painting of Tasmanian landscapes soon brought favourable reviews. He was a participant in the exploration, description and surveying of the western part of Tasmania. The paintings he produced of western Tasmania were purchased by the Tasmanian government under a special act of parliament.

After moving to NSW in 1880 Piguenit's subjects included the Darling, Nepean and Hawkesbury Rivers as well as the Lane Cove River close to his Hunters Hill home. At this time he became one of the founders of the Art Society of New South Wales. Later, during a visit to Tasmania he was noticed by Lady Hamilton, wife of Governor Robert Hamilton and many his drawings were purchased by the government for the Hobart gallery.

His Flood in the Darling was purchased for the National Art Gallery of New South Wales (now Art Gallery of New South Wales) in 1895. In 1898 and 1900 he visited Europe, exhibiting at London and Paris. Returning to Australia he won the Wynne Prize in 1901 with his Thunder storm on the Darling. In 1903 he was commissioned by the National Art Gallery of New South Wales trustees to paint Mount Kosciusko. By the end of the century he was regarded as the leading Australian-born landscape painter.

Piguenit died on 17 July 1914 at his home, "Saintonge", in the Sydney suburb of Hunters Hill. He was buried in the Field of Mars cemetery, where his headstone inscription reads: IN LOVING MEMORY OF WILLIAM CHARLES PIGUENIT DIED 17th JULY 1914; AGED 77 YEARS. "UNTO THE UPRIGHT THERE ARISETH LIGHT IN THE DARKNESS" (Field of Mars Cemetery: C of E, Sec. C. Grave 618).