Walter 'Walt' Simonson is an American comic book writer and artist, won numerous awards. His first professional comic book work was producing war stories for DC Comics and other publishers. He also did a number of illustrations for the Harry N. Abrams, Inc. edition of The Hobbit.

Walt Simonson is best known for his work on Marvel Comics titles in the 1980s and 1990s such as The Mighty Thor and X-Factor. He wrote and illustrated Thor for nine years, famously transformed Thor into a frog for three issues, also introducing the popular supporting character Beta Ray Bill (1983-1987). He has also worked on other Marvel titles such as Fantastic Four, on DC Comics books including Detective Comics, Manhunter, Metal Men and Orion (2000-2002), and on licensed properties such as Star Wars, Alien, Battlestar Galactica and Robocop vs. Terminator.

In addition to his work for both Marvel and DC, Simonson has also generated a considerable body of creator-owned work, like Ragnarök and Star-Slammers, which he inaugurated in 1972 as a Rhode Island School of Design thesis.

He is married to comics writer Louise Simonson, with whom he collaborated on X-Factor from 1988 to 1989. The couple made a cameo appearance in the Thor feature film (2011).