Westel Woodbury Willoughby (20 July 1867 – 25 March 1945), was an American academic.
He was the twin brother to William F. Willoughby. They were the sons of Westel Willoughby and Jennie Rebecca (Woodbury) Willoughby, their father having been a Major in the Union Army with the New York Volunteers, injured at the Battle of Chancellorsville. The elder Willoughby served on the Supreme Court of Appeals for Virginia following the war and presided over the Custis case in which the land for Arlington National Cemetery was awarded to the U.S. Government.
William Franklin Willoughby (1867–1960) was an author of public administration texts including works on budgeting. He often worked with his twin brother, Westel W. Willoughby.