Roy Matthews Mitchell (4 February 1884 – 27 July 1944) was a Canadian-American theatre practitioner who played an important role in little theatre in Canada and the United States. He was involved in the creation and was the first artistic director of the Hart House Theatre at the University of Toronto, and was an influence on Vincent Massey, Herman Voaden and Mavor Moore. In 1974 Moore wrote "in 1929, Roy Mitchell was a voice crying in the near-wilderness of Canada" and called him "the seer who said it all on our own doorstep nearly half a century ago." A later scholar wrote that Mitchell's "vision ... did not fully come to pass in his lifetime, nor did it subsequently."

Mitchell was born in Michigan in 1884 to Canadian parents. The family returned to Canada in 1886 and moved to Toronto in 1889, where Mitchell attended Harbord Collegiate Institute and then the University of Toronto. He became a journalist and worked at various newspapers, including the Toronto World until 1915.

Mitchell was a founding member of the Arts and Letters Club of Toronto in 1908, and there formed the Arts and Letters Players, which put on many shows at the club. The first was Interior by Maurice Maeterlinck in 1911; others included The Shadowy Waters by W. B. Yeats, The Workhouse Ward by Lady Gregory, and the North American premieres of Rabindranath Tagore's The Post Office (in 1914) and Chitra (in 1916). These productions, directed by Mitchell, "introduced skeptical Toronto audiences to the principles of theatrical modernism," and the Arts and Letters Players "became the foremost group in Toronto's amateur theatre."

Mitchell was an "ardent Theosophist," a belief shared with other Arts and Letters Club members such as Lawren Harris and Merrill Denison. He joined the Toronto Theosophical Society in 1910 and wrote a handbook, Theosophy in Action, in 1923. In 1925 Mitchell and philanthropist Dudley Barr founded the Blavatsky Institute to print Theosophical texts. In 1926 the Toronto Daily Star said his "connection with the Theosophical Society made his name prominent throughout Canada." Theosophy was important in his theatre work, and this was reflected in productions such as The Trojan Women at Hart House and in his book Creative Theatre.

Mitchell moved to New York City in 1916 to study and work in theatre, mostly in Greenwich Village. In 1917 he was technical director for the first season of the Greenwich Village Theatre. In 1918 he returned to Canada, and worked as Director of Motion Pictures at the Department of Information in Ottawa.

Mitchell knew Vincent Massey from the Arts and Letters Club, and worked with him in creating the Hart House Theatre, which opened in 1919. Mitchell moved back to Toronto be its first artistic director. Plays he directed there include:

Cymbeline was his last Hart House production. After two seasons, and disagreements with the Board of Syndics about concentrating on Canadian plays, he left. He spent two years on the west coast of Canada, then returned to Toronto, where for a while he taught scene design at the Ontario College of Art. Through the 1920s he lectured extensively on Theosophy and little theatre in Canada and the United States.

Mitchell married Jocelyn Taylor on 17 May 1926 at the Church of St. Mary Magdalene. She had worked with him on stage productions for several years, doing sets, costumes and lighting. The Toronto Daily Star announcement of the wedding described Mitchell as "author, lecturer, theatrical director, theosophical leader and onetime newspaperman" and Taylor as a "well-known artist and sculptress." In 1929 they moved to New York City. Mavor Moore wrote, "Mitchell left for New York to teach and write about the theatre Canada was not yet ready for."