Beveridge, the eldest son of Henry Beveridge, an Indian Civil Service officer and District Judge, and scholar Annette Ackroyd, was born in Rangpur, British India (now Rangpur, Bangladesh), on 5 March 1879.
William Beveridge was educated at Charterhouse, a leading public school near the market town of Godalming in Surrey, followed by Balliol College at the University of Oxford, where he studied Mathematics and Classics, obtaining a First in both.