Sir William Newzam Prior Nicholson (5 February 1872 – 16 May 1949) was a British painter of still-life, landscape and portraits.

He also worked as a printmaker in techniques including woodcut, wood-engraving and lithography, as an illustrator, as an author of children's books and as a designer for the theatre.

William Nicholson was born in Newark-on-Trent on 5 February 1872, the youngest son of William Newzam Nicholson, an industrialist and Conservative MP of Newark, and his wife Annie Elizabeth Prior, the daughter of Joseph Prior and Elizabeth (née Mallam) of Woodstock, Oxon.

[8] They were soon joined by Mabel's brother James, and not long after by Ellen Terry's son Edward Gordon Craig and his wife May, who had also recently eloped and married.

[9] William and Mabel Nicholson had four children: the celebrated painter Ben (1894–1982); (John) Anthony (1897–1918), who died of wounds in France during the First World War; Annie Mary "Nancy" (1899–1978), artist and wife of the poet Robert Graves; and the architect and designer Christopher "Kit" (1904–1948).

[4] In October 1919, Nicholson married Edith Minnie, daughter of Sir Lionel Phillips, first baronet,[11] and widow of Lieutenant-Colonel John Stuart-Wortley (killed in action, 21 March 1918),[12] who, under the name Elizabeth Drury, was also a painter.

According to Steen, they met in Andalucia in May 1935, and by mid-June were living together at Nicholson's mews studio in Apple Tree Yard, off Jermyn Street.

[8] From 1893 to 1898, Nicholson collaborated with his brother-in-law James Pryde on poster design and other graphic work including signboard painting and book illustration.