O'Casey, Seán, né John Casey (1880–1964). Irish-born playwright. After initial successes with The Shadow of a Gunman (1923), Juno and the Paycock (1924), and The Plough and the Stars (1926) he moved to England where he failed to live up to his early promise, instead writing volumes of memoirs and making embittered comments about more successful writers including Coward, Eliot, Greene, Orwell and Wodehouse.
O'Neill, Eugene Gladstone (1888–1953) American playwright, not noted for comedy or optimism of outlook. He disowned his daughter Oona, and both his sons killed themselves.
O'Neill, Norman Clifford (1937–2008). Cricketer. Batsman for New South Wales (1955–1967) and Australia (1958–1965).
O'Shea, Teresa Mary ('Tessie') (1913–1995). Singer and actress. Famous for songs such as 'Nobody Loves a Fairy when she's Forty.'
Occleve, Thomas (c. 1368–1426). Poet. Like Chaucer, whom he admired, he was a civil servant. His poetry has not won the same admiration as Chaucer's.
Ogden, Charles Kay (1889–1957). Linguist, philosopher and writer, the inventor and propagator of Basic English, an auxiliary international language of 850 words intended to cover everything necessary for day-to-day purposes.
Oldham, John (1653–1683). Poet. A satirist who imitated the classical satires of Juvenal. His best-known works are A Satire Upon a Woman Who by Her Falsehood and Scorn Was the Death of My Friend, written in 1678 and A Satire against Virtue, written in 1679. His translations of Juvenal were published after his death.
Oliver, Vic (né Victor Oliver von Samek) (1898–1964). Radio comedian. Married Winston Churchill's daughter, Sarah in 1936 (divorced in 1945).
Oppenheim, Edward Phillips (1866–1946). Prolific author of thrillers and romances.
Oppenheimer, Sir Ernest (1880–1957). German-born diamond merchant and financier, with extensive interests in South Africa.
Ordish, George (1904–1991). Entomologist, economist, pioneer of English viticulture, and author. Books include Wine-growing in England (1953); The Living House (1959, revised 1985); The Great Wine Blight (1972, revised 1986).
Orwell, George, pen name of Eric Arthur Blair (1903–1950). Essayist, and author of The Road to Wigan Pier, 1937; Homage to Catalonia, 1938; Coming Up for Air, 1939; Animal Farm, 1945; The English People, 1947; and Nineteen-eighty Four, 1949.
Osborne, John James (1929–1994). Playwright and actor. His early plays, from Look Back In Anger (1956) established him as one of the 'angry young men' of the 1950s. In later life he became something of an Establishment figure himself.
Osbourne, Lloyd (1868–1947). Author. Stepson of Robert Louis Stevenson, with whom he collaborated on The Wrong Box, 1889; The Wrecker, 1892; and The Ebb Tide, 1894.
Owens, James Cleveland ('Jesse') (1913–1980). American track and field athlete. He participated in the 1936 Summer Olympics in Berlin, Germany, where he achieved international fame by winning gold medals in the 100 meters, the 200 meters, the long jump, and as part of the 4x100 meter relay team.