In Chapter 15, the cockroach that shows up makes a "JOHJ" sound in reference to the language of the Hyper-Evolved cockroaches from TerraforMARS.
The same chapter features Shirogane using what he calls the "Karma Akabane technique" of biting his tongue til it bleeds. In this case, it's used so he doesn't pass out when he sees an cockroach, rather than the pain not allowing him to be stunned like how Karma used it.
The student who runs against Shirogane and Miko in the Student Council elections is named Hayato Hongo, a reference to the original Kamen Riders Takeshi Hongo and Hayato Ichimonji (his name even uses the same kanji as theirs).
The manga has a cameo of Nusret "Salt Bae" Gökçe during Chapter 96.
In Chapter 102, we see a LINE sticker of a bunny with a very Pop Team Epic-esque vibe.
In Chapter 109, Ishigami references the #MeToo movement. Sort Of.This is a bit of very liberal localization on the part of the fan scanlators for that chapter. A broadly similar joke is present in the original but has somewhat different connotations, and it written out entirely in the official English release.
Chapter 110
Ishigami explains to Shirogane why a mangaka sometimes takes a break. Shirogane then praises Ishigami for his knowledge:
All of the Student Council members mention real anime when asked about their favorites (Akage no Anne for Kaguya, the various works of Studio Ghibli for Fujiwara, Your Name for Ishigami, and Onegai My Melody for Iino).
After accidentally turning down Shirogane's offer for a date in Chapter 113, Kaguya tells Hayasaka to find a way to turn back time. Hayasaka responds with "Who do think I am, Doraemon?"
Gigako wears a Spetsnaz Helmet in Chapter 116, with Fujiwara correctly mentioning that it can withstand a headshot from a Kar98k rifle.
The Phantom Thief who stole all the heart-shaped balloons in Chapter 129 left a calling card referring to themselves as Arsene. Of course, the name wasn't chosen because of the reference, but rather what it translated to.
In Chapter 131, the fortune teller Yume is a direct reference to The Witch from ib: Instant Bullet.
In Chapter 140, Fujiwara mention Pretty Cure to Ishigami, as an Actor Allusion to Fujiwara's voice actress playing Cure Milky at the time of release.
In Chapter 149, the cast is shown playing Scotland Yard.
When Osaragi is discussing different types of female otakus in Chapter 158, furries are represented by Renamon. The Harry Potter franchise is also mentioned by name.
When Ishigami begins to exercise regularly, Fujiwara, in her shock, asks him if he got the idea from watching an anime. How Heavy Are the Dumbbells You Lift?'s adaptation aired just before the time of that chapter's release, which equally got a lot of otaku exercising.
Kazeno's favorite idol group is very obviously based on the real group Hinatazaka46.
The Tabletop Gaming Club's winter vacation chapter has Erika (in Japanese) simultaneously saying that they're a trio of psychopaths while also commenting that their imagined crime ring feels more like Psycho-Pass.
Ishigami is shown playing Apex Legends in Chapter 198.
Fujiwara mentions playing Among Us in Chapters 218-219.
In Chapter 225 Hikaru Oobayashi is playing Shadowverse while talking to Kaguya. The chapter was released while there was a Kaguya-sama collaboration event in the game.
Chapter 228 is pretty much all about the Discord App, and brings up Apex Legends again.
Chapter 229 continues the Apex Legends references by having Iino give it a try with Papa Shirogane. GoldenEye is also mentioned.
Chapter 270 takes place almost entirely on a Winecraft server.
Doujin Edition
In Chapter 1, Ishigami uses hand signals to tell Fujiwara "Pantsu maru mieru" (I can see your panties), just like Jean Pierre Polnareff.
Fujiwara and her little sister get into a Turf War with some young kids in Chapter 2, complete with being drawn in a way that clearly resembles Inklings.
Chapter 13, being about a "Freaky Friday" Flip, naturally references Your Name, and even implies that Miko ended up swapping bodies with Mitsuha.
In Chapter 27, Nagatoro can be seen offering her senpai some Valentine's Day chocolate.
Anime
Season 1
The animated opening is an homage to the opening songs of most James Bond films. With several direct references specifically to Skyfall's.
The anime adaptation of Chapter 28 references, of all things, a Trivago ad.
When the narrator is talking about summer vacation plans in episode 10, a shot of some boys playing Super Smash Bros. Ultimate with the Student Council as playable characters can be seen. An earlier scene also has a classic Batman (1966) scene transition, but with Fujiwara's head on a sunflower instead of the bat signal.
Episode 2 of the anime changes Shirogane's dialogue ever so slightly from the manga to sneak in a line from Kimi no Shiranai Monogatari.
Episode 8 adds in a reference to Joe's death scene from Tomorrow's Joe while Kaguya is helping Ishigami study.
Season 2
The scene of Fujiwara, Ishigami, Iino, and Osaragi walking in the opening was inspired by the band Madness's Nutty Train, specifically from their an 80s Honda commercials
The cover for the CD of the opening theme has the student council all wearing mouse ear headbands. Kaguya in particular has Mickey Mouse ears.
Episode 13:
There is a scene where the members of the student council are depicted as trains. Ishigami is represented by a blue steam engine.
Hayasaka parodies the fuse-lighting sequence from Mission: Impossible. The background music for this scene parodies the Madonna song "Vogue".
Episode 14:
When Kei is describing how her brother is at home, he's depicted as looking like Umaru.
Kaguya's mental court battle naturally includes several iconic Ace Attorney poses, including the finger pointing.
As Kaguya's classmates speculate as to why Miyuki wishes to speak to her, the background music becomes a parody of Dead or Alive's song "You Spin Me Round (Like a Record)".
One of Iino's reasons to choose Fujiwara to be her vice-president candidate is because she has always been admiring her piano talent since a kid, considering her prodigy. Similar reasoning to some of the characters's motivation from Your Lie in April, complete with the scene that resembles it.
Since Season 2 was released in the middle of the COVID-19 lockdown, the English subtitles for Episode 17 add in a couple of references to Social Distancing (though fan backlash resulted in them removing it).
Episode 20:
When Kaguya and Shirogane are thinking about the suspension bridge effect, there's a visual reference to the Ashes of Ariandel DLC from Dark Souls III.
When Iino's bookmark is first seen, it's placed in a book called Fifty Shape of Love.
When explaining the concept of a calming ritual pro athletes are shown as examples. Specifically they reference:
Ichiro Suzuki, a baseball player who would point his bat to the outfield and give his sleeve a small tug before every pitch. He played most of decade in the Japanese NPB league before jumping to the MLB for a further 18 years.
Jonny Wilkinson, a rugby player with a unique crouch and hand movements before each kick. Played for about 15 years in England and France.
Kohei Uchimura, a Japanese gymnast who competed from 2007 until 2022. He would often stretch his arms out in front of him before a vault. The imagery in the episode specifically references one of his best vaults at the 2010 Japan Cup.
Kaguya dances to "Vogue" while trying to find a pose for her routine.
At the end of the Soran Bushi sketch in Episode 22, Fujiwara is seen imitating Stevie Wonder.
While Kaguya argues with her on how to properly perform the Soran Bushi dance in the same episode, Fujiwara recreates Flashdance's iconic dousing scene from the film.
The booklet for Season 2's Blu-ray disc contains a 4-koma where Iino and Osaragi discuss Osaragi's Opaque Nerd Glasses. Osaragi uses them to deliberately appear uglier and repel unwanted suitors, which is why she calls them "Mystic Eye Killers".
The narrator's explanation of the parent-teacher career counseling ends with the classic rock-paper-scissors imagery of a snake, frog, and slug which are respectively labeled as Fire, Water, and Grass Type.
When Iino imagines her hypothetical prince, everyone is drawn◊ in the style of The Rose of Versailles. And it a bit of foreshadowing, the specific image it was parodying has the main character's love interest (André Grandier) in the same spot as Ishigami.
When Fujiwara shows off her balloon animal making skills inn Episode 31, the teddy bear she made is shown coming out of a house built into a tree. She also calls Shirogane a "sweet summer child" in the English Dub when she learns that he tried inflating balloons from the warehouse, which have degraded due to age and pop easily.
At the end of the episode, a pastiche of RADWIMPS song "Zenzenzense" plays as Tsubame announces the start of the School Festival. This serves to reference the romantic fantasy film Your Name.
When Makki-senhai is explaining how binaural audio is recorded, the dummy head starts acting like Max Headroom.
Seeing as the whole thing involves a Phantom Thief named Arsene who is stealing hearts, the anime can't resist throwing in a Persona 5 reference by having a pastiche of "Life Will Change" in the final scene. This also carries over to the opening scene of the following episode.
The English dub carries this over into a casting gag, with the calling card read by Sonny Strait, who had previously voiced the real Arsene's grandson, Lupin III.
Episode 35:
Kaguya is reading an article about Shirogane on the bulletin board when his hand emerges from the wall and pulls her into a monochrome environment with him, just like the music video for a-ha's "Take on Me". The background music is even a pastiche of said song.
Miyuki even quotes some of the lyrics of the actual song in the english dub.
When Fujiwara spontaneously gives the boy confessing to her a quiz, the background is the ruined Statue of Liberty on a beach from the ending of Planet of the Apes (1968).
Kaguya's panic over Ishigami potentially ruining her date with Shirogane is depicted in the style of Resident Evil, complete with changing camera angles, tank controls, and her Wallbonking. There's even a student advertising a haunted house nearby that's holding a sign reading Biotic Hazard, referencing the series' Japanese name Biohazard.
Episode 36:
As Hayasaka details her plan to help Kaguya confess her feelings to Miyuki, the screen changes to that of a Otome game displaying the couple's dialogue, while she and Hayasaka are represented in yukkuri form.
As Shirogane's Phantom Thief plan enters its final stages and the jewel the dragon is coiled around vanishes, the following exchange occurs in the dub.
Kaguya: Who saw fit to mess with the president's dragon ball?! Hayasaka: Copyright...
Episode 37:
Karen's reaction to seeing Kaguya and Shirogane's First Kiss is a frame for frame recreation of Kycilia's death in Mobile Suit Gundam.
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