Mary Letitia Somerville Bennett (9 January 1913 – 1 November 2005) was a British academic, best known for her tenure as Principal of St Hilda's College, Oxford between 1965 and 1980.
Born Mary Letitia Somerville Fisher, she was the daughter of historian H. A. L. Fisher and Lettice Fisher, the founder of the National Council for the Unmarried Mother and her Child. She was educated at Oxford High School. She obtained her first degree (in Classics) from Somerville College, Oxford, and then studied abroad, researching the grain supply of ancient Rome. During the Second World War she worked for the British Ministry of Information and for the BBC, and after the war went into the Colonial Office with responsibility at various times for Gibraltar, Malta and Cyprus. In 1955, she married senior civil servant John Sloman Bennett, who would be happy to take a back seat when she took over as Principal of St Hilda's from Kathleen Major.