Westel Woodbury Willoughby (20 July 1867 – 25 March 1945) was an American academic. He and his twin brother to William F. Willoughby were the sons of Westel Willoughby and Jennie Rebecca (Woodbury) Willoughby. Their lawyer father had been Major in the Union Army with the New York Volunteers, and after retiring due to injuries incurred at the Battle of Chancellorsville, served as a local prosecutor, then briefly as a trial judge and on the Supreme Court of Appeals for Virginia. Dr. Willoughby continued to live in Baltimore until his death on 25 March 1945.