Dennis Guilder is one of the protagonists of the Stephen King horror novel Christine, the other two being Arnie Cunningham (who is hypnotized by Christine) and Leigh Cabot. He is the only friend of Arnie and strongly goes against the idea of him buying Christine but he buys her anyway. Afterwards he gets into a fight between Arnie and the school bully Buddy Repperton who gets suspended and as revenge Buddy, Moochie, Richie and Don who are Buddy's thugs severely vandalise Christine.
After a series of car deaths starting with Moochie and ending with Don Vandenberg eventually Dennis and Leigh concoct a plan to destroy Christine and eventually do. After Christine is fully destroyed he still thinks that she is back and destroying all who stood up against her saving him for last.