John "Jack" Butler Yeats (29 August 1871 – 28 March 1957) was an Irish artist and Olympic medalist. W. B. Yeats was his brother.
Butler's early style was that of an illustrator; he only began to work regularly in oils in 1906. His early pictures are simple lyrical depictions of landscapes and figures, predominantly from the west of Ireland—especially of his boyhood home of Sligo. Yeats's work contains elements of Romanticism.