Sir Ronald Charles Lindsay GCB GCMG CVO PC (3 May 1877 – 21 August 1945) was a British civil servant and diplomat. He was Ambassador to Turkey from 1925 to 1926 and to Germany from 1926 to 1928, Permanent Under-Secretary for Foreign Affairs from 1928 to 1930 and Ambassador to the United States from 1930 to 1939.