During the car chase on campus, the action in one particular scene is sped up and a tune similar to "Yakety Sax", the iconic music from The Benny Hill Show (1969), can be heard. In the background, the building title reads "Benjamin Hill Institute for Film Studies"
When characters discuss the operation's (but also the film's) larger budget, Jenko states "I thought we had Cate Blanchett for the budget?!" This is one of the movie's many meta-references. 22 Jump Street opened on the same day in North America as another sequel, How to Train Your Dragon 2 (2014), which also starred Jonah Hill and Cate Blanchett.
When Jenko and Zook first bump into each other and Jenko drops his Q-tip into Zook's sandwich, they end up calling it a "meat cute". In movie terminology, a meet cute is when two romantic partners meet for the first time, foreshadowing their 'bromance'.
When Schmidt is driving the Lamborghini Murciélago, he comments that he feels like Batman. In Batman Begins (2005), Batman drives a Lamborghini Murciélago Roadster; in The Dark Knight (2008), Batman drives a Lamborghini Murciélago LP640.
When Schmidt and Jenko are spying on the frat boys with the cameras they just installed, the frat boys are debating whether or not to recruit Schmidt and have his Facebook page up in the screen behind them. On his Facebook page we can see activity that reads he "liked" Molly Tracey's photo. Molly is is Schmidt's love interest in 21 Jump Street (2012).
Jonah Hill is attacked by an octopus and yells "It's inking in my mouth!" Which is similar to a line in his earlier movie The Watch (2012) in which he yells "it's getting goo in my mouth!" about an alien that resembles an octopus.
After the plot is resolved, Jenko says, "We're getting too old for this shit." a line popularized by Danny Glover's character Roger Murtaugh in Lethal Weapon (1987), Lethal Weapon 2 (1989), Lethal Weapon 3 (1992) and Lethal Weapon 4 (1998). During the mock sequel credits, where Schmidt and Jenko play senior citizens, Schmidt states the same Glover quote. Jenko (amused) replies with "Nice."
On the Vietnamese church, below the name "Resurrection of the Holy Spectacle" is a Vietnamese phrase "Canh Tuong Thành Phuc Sinh" which translates to "The Easter Scene," another possible movie terminology reference for the resurrection of Jesus.
One of the more benign and amusing effects of the 2014 Sony Corporation cyber attack was the release of e-mails related to this film. Specifically, Channing Tatum sent several of them that loudly celebrated the film's huge box office opening in June 2014.
Zeta Theta Psi (the fraternity Jenko rushes in the film) are the letters of a real local sorority at Heidelberg University in Tiffin, Ohio. The sorority had not yet been officially recognized when production began.
Channing Tatum plays a much older cop pretending to be a college student, befriending Wyatt Russell's football-playing character in the process. Russell played a much older character posing as a college age guy trying to play baseball in Everybody Wants Some!! (2016).
When the Zeta frat members are discussing whether Doug (Schmidt) should become a member, there is an ad for a Sony Xperia Z on the right hand side of the Facebook page - paid product placement for Sony, the parent company of the studio. The characters also use Sony products (Jenko and Schmidt's phones, the tablet Jenko and Schmidt use to view the footage of their hidden cameras etc.
Seth Rogen appears as a replacement for Jonah Hill in a mock sequel. One of Hill's earliest roles was in Superbad (2007) as Seth, a character Rogen had envisioned playing himself when he began writing the script as a teenager.
Near the very ending of the film right before the end credits, as Jenko is trying to shoot Schmidt's arm (to make up for his failed attempt to take a bullet for Jenko earlier, trying to even it out from 21 Jump Street (2012) where Jenko takes a bullet for Schmidt), right behind Schmidt is a graffiti art consisting a pile of the number: 4. This is a nod to the first film during the high school drug scene where Jenko, on drugs, is constantly writing the number 4 on the blackboard and yells his famous line: "F*** you science!"
The closing credits montage of potential sequel ideas was based on general discussions that directors Phil Lord and Christopher Miller had discussed for real franchise editions. In addition, Seth Rogen's cameo as "Schmidt" came about from him successfully recruiting Channing Tatum to play a brief, memorable role in This Is the End (2013); Tatum and Jonah Hill both asked Rogen to appear in the credits and he immediately accepted the offer.
During the fight with Jenko and the Ghosts twin bodyguards, one of the spring breakers climbs onto Jenkos back and he uses her as a weapon. By doing so he spins the girl a couple times while hitting the guards and then he kisses her. This is similar and a nod to Channing Tatum's earliest role in the dance drama Step Up (2006).
In the final scene at the beach, where Jenko is about to shoot Schmidt in the arm to even it up between them, you can see a Yin and Yang symbol graffitied on the blue wall - the Yin and Yang symbol was discussed by the professor at the University of Internet at the start of the movie.