"Treehouse of Horror" is the third episode of the second season of the American animated television series The Simpsons. It originally aired on the Fox network in the United States on October 25, 1990. The episode was inspired by 1950s horror comics, and begins with a disclaimer that it may be too scary for children. It is the first Treehouse of Horror episode. These episodes do not obey the show's rule of realism and are not treated as canon. The opening disclaimer and a panning shot through a cemetery with humorous tombstones were features that were used sporadically in the Treehouse of Horror series and eventually dropped. This is also the first episode to have the music composed by Alf Clausen.

The second season of the animated television series The Simpsons originally aired on the Fox network between October 11, 1990, and July 11, 1991, and contained 22 episodes, beginning with "Bart Gets an "F". Another episode, "Blood Feud", aired during the summer after the official season finale. The executive producers for the second production season were Matt Groening, James L. Brooks, and Sam Simon, who had also been executive producers for the previous season. It was produced by Gracie Films and 20th Century Fox Television. The DVD box set was released on August 6, 2002, in Region 1, July 8, 2002 in Region 2 and in September 2002 in Region 4. The episode "Homer vs. Lisa and the 8th Commandment" won the Primetime Emmy Award for Outstanding Animated Program, and was also nominated in the "Outstanding Sound Mixing for a Comedy Series or a Special" category.