William Grefé (born 1930) is an American writer and director of films, best known for his work in the exploitation field. For most of his career, he has worked in Florida. He also worked for several years with Ivan Tors.

In 2009 a documentary was released about his work called From the Swamp: The Films of William Grefe. In 2020 a four-disc Blu-ray collection He Came from the Swamp: The William Grefé Collection will be released by Arrow Video.