Sidney Colvin (18 June 1845–1927) was an English literary and art critic.
He was born at Norwood, London. A scholar of Trinity College, Cambridge, he became a fellow of his college in 1868. In 1873 he was Slade professor of fine art, and was appointed in the next year to the directorship of the Fitzwilliam Museum.
In 1884 he moved to London on his appointment as keeper of prints and drawings in the British Museum. His chief publications are lives of Landor (1881) and Keats (1887), in the English Men of Letters series; the Edinburgh edition of R. L. Stevenson's works (1894-1897); editions of the letters of Keats (1887), and of the Vailima Letters (1899), which R. L. Stevenson chiefly addressed to him; A Florentine Picture-Chronicle (1898), and Early History of Engraving in England (1905).
In the field both of art and of literature, Colvin's fine taste, wide knowledge and high ideals made his authority and influence extend far beyond his published work.