James Williams Riddleberger (September 21, 1904 – October 17, 1982) was an American diplomat and career foreign service officer.

After the war, he became the chief political adviser to General Lucius D. Clay and later to John J. McCloy in occupied Germany.

[1] After Yugoslavia broke away from the Soviet orbit of influence in 1948, Riddleberger was credited with persuading Josip Broz Tito to rebuff coaxing by Nikita Khrushchev to return.

He took on leadership roles, serving as president of Diplomatic and Consular Officers Retired and as honorary chairman of the Population Crisis Committee.

His daughter, Antonia Riddleberger, was married to diplomat Monteagle Stearns (1924–2016),[4] who served as United States Ambassador to Greece from August 1981 through September 1985.