List of The Simpsons Treehouse of Horror episodes

"Treehouse of Horror", also known as "The Simpsons Halloween Specials", is a series of Halloween-themed episodes of the animated sitcom "The Simpsons", each consisting of three separate, self-contained segments. These segments usually involve the family in some horror, science fiction, or supernatural setting and always take place outside the normal continuity of the show and are therefore considered to be non-canon.
The original "Treehouse of Horror" episode aired on October 25, 1990 and was inspired by EC Comics Horror tales. Before "XI", which aired in 2000, every episode has aired in the week preceding or on October 31; "II" and "X" are the only episodes to air on Halloween. Between 2000 to 2008 and 2010, due to Fox's contract with Major League Baseball's World Series, episodes had originally aired in November; since 2011, each "Treehouse of Horror" episode has aired in October, with the exception of Season 32's XXXI, which was originally scheduled for October 18, but was postponed to November 1 due to the 2020 NLCS reaching game 7. This was the first time in 10 years that a Treehouse of Horror episode aired in November.
From "Treehouse of Horror" to "XIII", all three segments were written by different writers and in some cases there was a fourth writer that wrote the opening and wraparound segments. The original episode even had three different directors. Starting with season fifteen's "XIV", only one writer was credited as having written a "Treehouse of Horror" episode, and the trend has continued since.
As of 2020, there are thirty-one "Treehouse of Horror" episodes, with one airing every year. The 31st season included a Thanksgiving-themed spinoff, "Thanksgiving of Horror". They are known for being more violent than an average "Simpsons" episode and contain several different trademarks, including the alien characters Kang and Kodos who have appeared in every episode. Quite often the segments will parody well-known movies, books, radio shows, and television shows. "The Twilight Zone" has been parodied quite often, and has served as the inspiration for numerous segments.