List of The Simpsons Treehouse of Horror episodes
The production code refers to the code assigned to the episode by the production team. The first two characters refer to the season the episode was made for. The second season is 7Fxx, the third is 8Fxx and the fourth is 9Fxx. After that, the fifth season started with 1F and continued in order until season nine (which was 5F). Starting with season ten, the production codes started with AABF, with the first letter changing for each season (i.e. BABF, CABF, etc.) The number at the end of the code is the order in which that episode was produced during that production run.