John Courtenay Trewin OBE (4 December 1908 – 16 February 1990) was a British journalist, writer and drama critic. Trewin was born in Plymouth, Devon, although both his parents were Cornish. He was educated at Plymouth College and in 1926 joined the as a cub reporter. He moved to London in 1932 and joined the Morning Post, transferring to The Observer in 1937. He served as drama critic on the paper for more than 60 years. His also wrote a drama column for The Listener (1951–57), and contributed regular notices to Punch (1944–45), John O'London's Weekly (1945–54), The Sketch (1947–59), the Illustrated London News (1947–88), The Lady (from 1949) and the Birmingham Post.