Frank Diehl Fackenthal (February 22, 1883 – September 5, 1968) was an American educator.
Fackenthal graduated from Columbia University in 1906. He served Columbia as chief clerk (1906–10), secretary (1910–37), and provost (1937–48). Between the retirement of Nicholas Murray Butler (1945) and the installation of General Dwight D. Eisenhower as president (1948), Dr. Fackenthal was acting president of the university, retaining his post as provost. After his retirement (1948) from the university he served as educational consultant to the Carnegie Corporation (1948–52) and then as president of the Columbia University Press (1953–58). His principal speeches as acting president were published as The Greater Power and Other Addresses (1949).