Clifford Leech (1909–1977) was a prolifically published British-born professor of English at University College at the University of Toronto 1963-74. His contribution to Christopher Marlowe studies was considered "historically important." In Canada he was considered a "distinguished scholar." His publications mainly concerned Elizabethan and Jacobean dramatists, including William Shakespeare, John Webster and John Ford. He also wrote a book on American playwright Eugene O'Neill. Leech's published reviews include one on a Canadian play, The Last of the Tsars, produced at Stratford, Ontario in 1966 on the subject of the last Russian czar.
Leech was a scholarly colleague of Northrop Frye.
He obtained his M.A. at the University of London in 1932 with an essay on the poet Thomas Southerne. His doctoral thesis at Queen Mary, University of London was "Private performances and amateur theatricals (excluding the academic stage) from 1580 to 1660" (1935).
While teaching at the University of Durham, Leech became Censor then, in 1948, the first Principal of St Cuthbert's Society, one of Durham's collegiate bodies. There he was acclaimed "not only in the quality of his scholarship but also in his services to the Society". He stepped down at Easter 1952. His portrait, by Thomas William Pattison (1894-1983) hangs in the college hall of St Cuthbert’s in Durham.
In 1964 he succeeded A. S. P. Woodhouse as chairman of the Department of English at University College at the University of Toronto. In 1971 he gave up being general editor of the Revels Plays, a series he had conceived in the mid-1950s in imitation of the New Arden Shakespeare, applying that edition's methods of scholarship to other English plays before 1700. Leech turned over the Revels Plays to F. David Hoeniger.