"Treehouse of Horror XXXI" is the fourth episode of the thirty-second season of the American animated television series The Simpsons, and the 688th episode overall as well as the thirty-first "Treehouse of Horror" episode. It aired in the United States on Fox on November 1, 2020. The episode was directed by Steven Dean Moore, and written by Julia Prescott.

The thirty-second season of the American animated television series The Simpsons premiered on Fox on September 27, 2020, and ended on May 23, 2021. This season contained twenty-two episodes. On February 6, 2019, the season was ordered along with the previous season. This season includes the series' 700th episode "Manger Things".