!! The TV show:
* BadExportForYou: Inverted - the American [=DVDs=] suffer from terrible ClumsyCopyrightCensorship, with missing music and scenes, but the full version can be found in some foreign releases. On the German DVD sets the full original audio is included even in the English tracks on some episodes, although other episodes only have correct music on the German audio track.
* DawsonCasting: By the ''cops'' inside the show.
** As well as the students, especially in later seasons.
* YouLookFamiliar: Two prominent examples are Jason Priestly and Lochlyn (Rick) Munro, who played different characters in multiple episodes.

!! The film:
* ActorAllusion:
** Ice Cube's verse from "Straight Outta Compton" plays as he talks to Jenko and Schmidt.
** When planning for their party, Schmidt and Jenko jokingly wonder how they are going to get alcohol, since neither one has a fake ID, a reference to ''Film/SuperBad''. Jonah Hill and Dave Franco were also high school classmates in that film too.
** When Schmidt and Jenko are being briefed on HFS, two usernames can be seen as 'Chanchan' and 'Brielar'.
** A partial example. Molly is starring in a production of ''Peter Pan''. Brie Larson had auditioned to play Wendy in the [[Film/PeterPan 2003 version]].
* DawsonCasting: Although the movie parodies this with Jonah Hill (29) and Channing Tatum (32) trying to pass for high school students, it's still played straight with the actors playing the actual high school students. Brie Larson was 22 and Dave Franco was 27, both playing 18-year-olds.
* DyeingForYourArt: Jonah Hill actually lost forty pounds for the movie, in order to be able to do some of the more physically demanding stunts.
* PlayingAgainstType:
** The directors of these films are best known for ''WesternAnimation/CloudyWithAChanceOfMeatballs'' and ''WesternAnimation/TheLEGOMovie''. Lampshaded by a TV spot for ''The LEGO Movie'', which played up that it was from the directors of ''21 Jump Street'' and ''Film/TwentyTwoJumpStreet'', then adding, "Neither of which have anything to do with this movie."
** At the time Channing Tatum was pretty solidly typecast as an action star or romantic lead. This marked his first big comedy and, along with ''Film/MagicMike'', showed that he had [[LeslieNielsenSyndrome quite a flair for it]].
* TooSoon: In the audio commentary, it is mentioned that the line "Doing cocaine with Willie Nelson's horse" was originally "Doing cocaine with Whitney Houston's niece." This was changed because of Houston's death shortly before the editing of the movie was supposed to be finished, and at the last minute they had to call the actor to come in and dub over a new line.
* WhatCouldHaveBeen: Emma Stone was considered for Molly, but she was too busy filming ''Film/TheAmazingSpiderMan''.

!! General:
* TruthInTelevision: Whether or not it was deliberately inspired by the show, using young-looking police officers undercover as high school students has ''actually been done''. Read about the real-life example of Alex Salinas [[http://abcnews.go.com/blogs/headlines/2012/03/real-life-21-jump-street-undercover-cop-returns-to-high-school/ here]].