Philip Sandeman Ziegler (born 24 December 1929) is a British biographer and historian.
Born in Ringwood, Hampshire, Ziegler was educated at St Cyprian's School, Eastbourne, and went with the school when it merged with Summer Fields School, Oxford. He attended Eton College and New College, Oxford, graduating with a degree in Jurisprudence with highest honours before joining the British Foreign Service. In the Foreign Service, he served in Laos, Pretoria and Bogotá, as well as with the Delegation to NATO in Paris.
In 1967 he retired from the Foreign Service, and joined the publishers Collins. Originally intending to be a novelist, he began a career as biographer with his life of Talleyrand's lover, the Duchess of Dino. He was editor in chief at Collins from 1979-80. He has written in various journals and newspapers including The Spectator, The Listener, The Times, The Daily Telegraph and History Today.