Wilde was born Olivia Jane Cockburn in New York City on March 10, 1984. She grew up in the Georgetown neighborhood of Washington, D.C. while spending summers at Ardmore in Ireland. She attended Georgetown Day School in Washington, D.C. and Phillips Academy in Andover, Massachusetts, graduating in 2002. Wilde derived her surname from Irish author Oscar Wilde, and started using it while in high school to honor the writers in her family, many of whom used pen names. She was accepted to Bard College, but deferred her enrollment three times in order to pursue acting. She then studied at the Gaiety School of Acting in Dublin. For a short time, Wilde's family also had a house in Guilford, Vermont. Wilde's father, Andrew Cockburn, is a British journalist; he was born in the London suburb of Willesden and raised in Ireland. Her mother, Leslie Cockburn (Redlich), is an American producer on 60 Minutes and journalist. She has a sister five years older and a brother nine years younger. Her grandfather, British novelist Claud Cockburn, and his sons Alexander and Patrick Cockburn also worked as journalists and her aunt, Sarah Caudwell, was a writer. Writer Christopher Hitchens was the Cockburn family's tenant in Washington, D.C. and served as Wilde's babysitter. Some of Wilde's paternal Scottish ancestors were upper-class and lived in many locations at the height of the British Empire, including Peking (where her paternal grandfather was born), Calcutta, Bombay, Cairo, and Tasmania. The Cockburns descend from the lawyer, judge, and literary figure Henry Cockburn, Lord Cockburn. One of Wilde's great-great-grandfathers, Henry Arthur Blake, was governor of Hong Kong. Through her father's family, Wilde is related to George Cockburn, who was responsible for burning down Washington, D.C. during the War of 1812. Aside from Scottish, Wilde's ancestry includes English, German, Irish, and Manx; she is also of 1/64th Sephardic Jewish descent through her great-great-great-great grandfather, Ralph Bernal (1783–1854), a British Whig politician and actor.