Robert Sholto Johnstone Douglas (3 December 1871 – 10 March 1958), known as Sholto Douglas, or more formally as Sholto Johnstone Douglas, was a Scottish figurative artist, a painter chiefly of portraits and landscapes.

He was born in Edinburgh, a member of the Queensberry family, part of the Clan Douglas. He was the son of A. H. Johnstone Douglas DL JP of Lockerbie (1846–1923) and his wife Jane Maitland Stewart, and the grandson of Robert Johnstone Douglas of Lockerbie, himself the son of Henry Alexander Douglas, a brother of the sixth and seventh Marquesses of Queensberry. His paternal grandmother, Lady Jane Douglas (1811–1881), was herself a daughter of Charles Douglas, 6th Marquess of Queensberry, so she was her husband's first cousin. Douglas's third cousin and contemporary John Douglas, 9th Marquess of Queensberry (1844–1900) was famous for the rules of the sport of boxing. Another cousin was Lady Florence Dixie, the war correspondent and big game hunter.

Douglas studied art in London, at the Slade School of Fine Art and also in Paris and Antwerp.

Douglas's cousin Lord Alfred Douglas, or 'Bosie', was a close friend of the writer Oscar Wilde. When Wilde sued Bosie's father for libel when accused of "posing as a somdomite" (sic), this led to Wilde's downfall and imprisonment. In 1895, when during his trial Wilde was released on bail, Sholto Johnstone Douglas stood surety for £500 of the bail money.

In his Noel Coward: A Biography (1996), Philip Hoare writes of "...late nineteenth-century enthusiasts of boy-love; writers, artists and Catholic converts inclined to intellectual paedophilia, among them Wilde, Frederick Rolfe, Sholto Douglas and Lord Alfred Douglas."

He was at home in Scotland as a painter and as a sportsman, shooting, riding and sailing. He kept ponies brought back from a visit to Iceland. He came to attention at the Royal Academy by being the first artist to hang a painting there of a motor car, but was best known for his portraits and his Scottish landscapes, which "...portrayed, with a truly poetic sense of atmosphere, the subtle half-tones of his native countryside".

In 1897, Douglas visited Australia and New Zealand. His uncle John Douglas, a former Premier of Queensland and Governor of New Guinea, arranged for the author R. W. Semon to take Douglas with him on a visit to New Guinea. Semon wrote "This young Scotsman was just then staying with his uncle on Thursday Island, being on his way back to Europe after a voyage to Australia and New Zealand."