Jonathan Gems (born 1952, London) is a British playwright and screenwriter mostly known for his work on Mars Attacks!, directed by Tim Burton. He also wrote the film's novelization.
The son of the playwright Pam Gems, Gems wrote a number of plays for theatres on the London fringe before gradually turning to screenwriting. As well as Mars Attacks!, Gems did uncredited rewrite work on Batman. Gems has written a number of unproduced scripts for Burton, including a Beetlejuice sequel titled Beetlejuice Goes Hawaiian, an updating of Edgar Allan Poe's "The Fall of the House of Usher" set in Burbank, California, The Hawkline Monster, a cowboy/monster movie that was to star Clint Eastwood and Jack Nicholson and Go Baby Go, a beach movie in the style of Russ Meyer.
- The Tax Exile (produced 1979)
- Naked Robots (produced 1980)
- The Paranormalist (produced 1982)
- Susan's Breasts (produced 1985)