Marc Behm (12 January 1925 in Trenton, New Jersey – 12 July 2007 in Fort-Mahon-Plage, France) was an American novelist, actor, and screenwriter, who lived as an expatriate in France. Behm co-wrote the screenplay for the Beatles' Help! (1965) and conceived the story for the film Charade (1963). His best and most well-known literary work is the crime novel Eye of the Beholder (1980), which was adapted twice for the screen, in 1983 and in 1999.

Behm developed a fascination for French culture while serving in the U.S. Army during World War II. He later had acting roles on several television programmes in France before moving there permanently.