Sir John Ronald Leon, 4th Baronet, known professionally as John Standing, is an English actor.
Standing began his career in Peter Brook's 1955 production of Titus Andronicus starring Laurence Olivier and wife Vivien Leigh and later played leading parts in Oscar Wilde's The Importance of Being Earnest, Christopher Fry's Ring Round the Moon, A Sense of Detachment by John Osborne, and Noël Coward's Private Lives, with Maggie Smith. He was nominated for an Olivier award (1979) for Close of Play at the National Theatre. He made his film debut in The Wild and the Willing (1962), going on to appear in King Rat (1965), Walk, Don't Run (1966), The Psychopath (1966), The Eagle Has Landed (1976), The Elephant Man (1980), Nightflyers (1987), Mrs Dalloway (1997) and A Good Woman (2004).
One of his first major television roles was as Sidney Godolphin in the BBC twelve-part serial, The First Churchills (1969). Other television appearances include Tinker, Tailor, Soldier, Spy (1979); the ITV sitcom The Other 'Arf (1980–84), with Lorraine Chase; The Choir (1995) and King Solomon's Mines (2004).
In July 2010, it was confirmed that he would be appearing as Jon Arryn in the HBO series Game of Thrones, based on Martin's A Song of Ice and Fire novels.