Robert Stephen Ingersoll (January 28, 1914 – August 22, 2010) was an American businessman and former diplomat.
Ingersoll was Chief executive officer and Chairman of the Board of BorgWarner and his international business experience was an important factor in his selection as United States Ambassador to Japan from 1972 to 1973, and assistant Secretary of State for East Asian and Pacific Affairs from 1973 to 1974, both during President Richard Nixon's term in office.
He served as United States Deputy Secretary of State from 1974 to 1976 under both Presidents Nixon and Gerald Ford.