Philip Henry Kerr, 11th Marquess of Lothian, (18 April 1882 – 12 December 1940), known as Philip Kerr until 1930, was a British politician, diplomat and newspaper editor. He was private secretary to Prime Minister David Lloyd George between 1916 and 1921. After succeeding a cousin in the marquessate in 1930, he held minor office from 1931 to 1932 in the National Government headed by Ramsay Macdonald. From 1939 until his death in December 1940 he was Ambassador to the United States.