Robert Hugh Ferrell (born May 8, 1921, in Cleveland, Ohio) is an American historian and author of several books on Harry S. Truman and the diplomatic history of the United States. He served in the U.S. Army Air Forces during the Second World War and was an intelligence analyst in the U.S. Air Force during the Korean War. He received a B.S. in Education from Bowling Green State University in 1946 and a PhD from Yale University in 1951, where he worked under the direction of Samuel Flagg Bemis and his dissertation won the John Addison Porter Prize. He went on to win the 1952 Beer Prize for his first book, Peace In Their Time, a study of the making of the Kellogg-Briand Pact.
Ferrell taught for many years at Indiana University in Bloomington, starting as an Assistant Professor in 1953 and rising to Distinguished Professor of History in 1974. He has held several notable visiting professorships, including Yale University in 1955 and the Naval War College in 1974. He supervised thirty-five PhD. students from 1961 to 1988.