(William) Denis Johnston (18 June 1901 – 8 August 1984) was an Irish writer. Born in Dublin, he wrote mostly plays, but also works of literary criticism, a book-length biographical essay of Jonathan Swift, a memoir and an eccentric work of philosophy. He also worked as a war correspondent, and as both a radio and television producer for the BBC. His first play, The Old Lady Says No!, helped establish the worldwide reputation of the Dublin Gate Theatre; his second, The Moon in the Yellow River, has been performed around the globe in numerous productions featuring such actors as Jack Hawkins, Claude Rains and Errol Flynn, although not all in the same production. He played a minor role in the 1935 film version of John Millington Synge's Riders to the Sea.
Johnston was a protégé of WB Yeats and Shaw, and had a stormy friendship with Sean O'Casey. He was a pioneer of television and war reporting. He worked as a lawyer in the 1920s and 1930s before joining the BBC as a writer and producer, first in radio and then in the fledgling television service. During the Second World War he served as a BBC war correspondent, reporting from El Alamein to Buchenwald. For this he was awarded an OBE 1945. He then became Director of Programmes for the television service.
Johnston later moved to the United States and taught at Mount Holyoke College, Smith College and other universities. He kept extensive diaries throughout his life, now deposited in the Library of Trinity College, Dublin, and these together with his many articles and essays give a distinctive picture of his times and the people he knew. He received honorary degrees from the University of Ulster and Mount Holyoke College and was a member of Aosdána.
- The Old Lady Says 'No!' (1929)
- The Moon in the Yellow River (1931)
- A Bride for the Unicorn (1933)
- Storm Song (1934)
- Blind Man's Buff (1936) (with Ernst Toller)
- The Golden Cuckoo (1939)
- The Dreaming Dust (1940)
- A Fourth for Bridge (1948)
- 'Strange Occurrence on Ireland's Eye' (1956)
- Tain Bo Cuailgne – Pageant of Cuchulainn (1956)
- The Scythe and the Sunset (1958)
- In Search of Swift (1959)
- John Millington Synge (1965)
- Nine Rivers from Jordan (1953)
- Orders and Desecrations (1992) (ed. Rory Johnston)
- The Brazen Horn (1976)
- Adams, Bernard. Denis Johnston: A Life. Lilliput Press, 2001.
- Igoe, Vivien. A Literary Guide to Dublin. Methuen, 1994.
- Denis Johnston fonds at University of Victoria, Special Collections