Egon Spengler, PhD is a fictional character from the Ghostbusters franchise. He appears in the films Ghostbusters, Ghostbusters II, and Ghostbusters: Afterlife, in the animated television series The Real Ghostbusters and Extreme Ghostbusters, and in the video games Ghostbusters: The Video Game and Ghostbusters Beeline. Egon was portrayed by Harold Ramis in the films and voiced by him in Ghostbusters: The Video Game and Lego Dimensions, and voiced by Maurice LaMarche in the cartoon series. He is a member of the Ghostbusters and one of the three doctors of parapsychology, along with Dr. Peter Venkman and Dr. Ray Stantz.

The Ghostbusters franchise consists of American supernatural comedies, based on an original concept created by Dan Aykroyd and Harold Ramis in 1984. The plot follows a group of eccentric New York City parapsychologists who investigate and eliminate ghosts, paranormal manifestations, demigods, and demons. The franchise expanded with licensed action figures, books, comics, video games, television series, theme park attractions, and other branded merchandise.