William Patrick Roberts (5 June 1895–20 January 1980) was a British artist.
In the years before the First World War Roberts was a pioneer, among English artists, in his use of abstract images. In later years he described his approach as that of an "English Cubist". In the First World War he served as a gunner on the Western Front, and in 1918 became an official war artist. Roberts's first one-man show was at the Chenil Gallery in London in 1923, and a number of his paintings from the twenties were purchased by the Contemporary Art Society for provincial galleries in the UK. In the 1930s it could be argued that Roberts was artistically at the top of his game; but, although his work was exhibited regularly in London and, increasingly, internationally, he always struggled financially. This situation became worse during the Second World War – although Roberts did carry out some commissions as a war artist.
Roberts is probably best remembered for the large, complex and colourful compositions that he exhibited annually at the Royal Academy summer exhibition from the 1950s until his death. He had a major retrospective at the Tate Gallery in 1965, and was elected a full member of the Royal Academy in 1966. There has recently been a revival of interest in the work of this artist who always worked outside the mainstream.