John Lee Mahin (23 August 1902 – 18 April 1984) was the last screenwriter to work on the script of the 1939 MGM film The Wizard of Oz. Mahin was the son of a successful advertising executive, also named John Lee Mahin. The younger Mahin attended Harvard University for a couple of years; he then left for a newspaper job, and became a protege of Ben Hecht. He also acted for a time, including an appearance in a play by Eugene O'Neill. His screenwriting career began in the early 1930s; he penned scripts for Treasure Island (1934) and Captains Courageous (1937) among other films. He also made uncredited contributions to a number of significant pictures, including Scarface (1932), A Star is Born (1937), and The Yearling (1946), among others.