"Osomatsu-kun Returns" is already packed to the brim with these, nearing Gintama levels:
- There's the obvious Boy Band shoutout to Uta No Prince Sama.
- Their band's name evokes F4 (Flower 4), a group of popular rich kids from the influential shojo manga series Hana Yori Dango.
- The Geass symbol appears on F6!Ichimatsu's necklace. He also does the same sweeping hand gesture that Lelouch often does earlier on in the episode. These make sense, as Ichimatsu and Lelouch share the same voice actor.
- The siblings sans Choromatsu each come up with weird ways to attract modern audiences, as much as bringing in Haikyuu!!, Kuroko no Basuke, and Yowamushi Pedal among other manga.
- Jyuushimatsu cosplays as Honoka after Osomatsu suggests they do a Moe idol show.
- Osomatsu gives his opinion on how their show should develop, and brings up a drawing of the sixtuplets dressed as the members of Fist of the North Star, and another showing nonuplets dressed as the members of Love Live!.
- The walls of the fancy academy they are in invokes the city walls of Attack on Titan. The Matsunos (again with Choromatsu not subscribing to the madness) also do a shot-for-shot remake of the first fight with the Colossal Titan, with a giant Chibita subbing in for the Titan.
- A more subtle example of this is that in a way this entire scene is being straight-manned by a very furious Levi.
- Goku, Ichigo, a Pokémon trainer and his Totoro, Usagi, Koro Sensei, Doraemon, and Naruto also join the fight against Chibi-Titan, albeit being the Matsuno brothers and their friends in disguise.
- Jyuushimatsu is briefly seen playing a pachinko machine resembling The Bog from Kaiji.
"Let's Get a Job"/"The Melancholoy of Osomatsu-kun"
- The boss of Black Factory gives us one long shout-out to Kaiji, both in the way he's designed and the speech he gives the brothers being eerily reminiscent of one of Tonegawa's speeches. And of course, there's the infamous "zawa zawa" effect seen throughout the scene.
- When Osomatsu finds Choromatsu at Nyaa's concert he screams "I love you, Reika!". Reika is a pretty famous cosplayer in and out of Japan.
- Considering her last name is Hashimoto, he could also be referring to famous Japanese model Reika Hashimoto instead.
- "Tidbits Collection" opens with a shot of the Sun coming up over the planets, complete with a Suspiciously Similar Song.
- The entire "Pachinko Police" sketch was a homage to the infamous "Absolutely No-Laughing 24 Hour Police" punishment game from Gakki no Tsukai.
- The "OAW" segment has one of the Matsuno brothers in a reverse bear trap machine, terrorized by a talking doll. The scenario even goes through numbered sequels after trying to determine which brother to torture!
- Dekapan becomes Dekapanman during three of the sketches.
- Some of the eyecatches in "Tidbits Collection" parody Mega Man and Street Fighter II.
"Let's Become Independent"/"This Is Totoko"
- In "Let's Become Independent", Ichimatsu wears a suit and hairstyle heavily resembling Hide of X Japan. Similarly, Jushimatsu is put in a getup resembling Toshi of the same band.
- One scene shows Osomatsu reading Southern Cross Kid, a relatively old manga by Ken Ishikawa.
"It's a Birthday Party, Dajo"/"Iyami's Great Discovery"
- President Obama shows up to ask Hatabou for advice, and President Hollande greets Iyami later on.
- In "Iyami's Great Discovery", Iyami points out that people have been doing his "Sheeeeh!" Pose for years (and with pictures to prove it, too), including Godzilla◊, Sadaharu Oh and even John Lennon◊.
- One of the race horses Iyami bets on ends up running so fast he disappears in a flash of light, exceeding time and space.
"Todomatsu and the 5 Demons"/"To the North"
- "Four" had Osomatsu dress up as Bruce Lee circa Game of Death.
- In "To the North", one man had a pink Funassyi on the back of his jacket.
- The same skit opens with Dekapan and Dayōn riding motorcycles through the American Southwest, only to be harassed by some guys in a pickup truck, before their bikes ultimately crash and explode. Their motorcycles even look just like the ones from the movie.
- Later on in that skit, there is an homage to the Wild ARMs series that resembles some iconic scenes in the opening animations to Wild ARMs 1 and Wild Arms 2, complete with music that sounds like it came from one of the game's OST.
"The Calming Osomatsu"/"Totoko's Dream"
- In "The Calming Osomatsu", one of the killer's victims is drowned in a manner similar to the poster of the 1976 mystery film The Inugami Family.
- The false killer looks like Jason.
- Detective Osomatsu is dressed like Sherlock Holmes, and, at one point, does Sailor Moon's famous In the Name of the Moon pose.
- While trying to boost Totoko's idol career, the boys make a horror TV special about a monstrous human/fish hybrid from the Amazon.
- The boys try to star Totoko in a fishing film titled The Idiots' Fishing Diary.
"Chibita and Oden"/"Jyushimatsu Falls in Love"
- Karamatsu's mistaken readings of "Jyushimatsu in Love" ("A Night at 14") and "Chibita and Oden" ("Oh My Little Oden") were references to Yutaka Ozaki's singles "A Night at Fifteen" (15 no Yoru) and "OH MY LITTLE GIRL".
- Chibita's lecture about oden contains a parody of the ape scene from 2001: A Space Odyssey.
- During "Jyuushimatsu Falls in Love", one of the outfits the brothers make Jyushi wear includes the Stone Mask as a face piece.
- Matching Ichimatsu's Hide cosplay from episode 3, Jyuushimatsu also briefly dresses up as X Japan's Toshi.
"Iyami and Chibita's Rental Girlfriend"
- The face Choro makes in "Iyami and Chibita's Rental Girlfriend" is a shoutout to a panel from Kyofu Shinbun.
- When Iyami accidentally lets his Verbal Tic slip, he tries for a Last-Second Word Swap and manages to replace "-zansu" with "Zangief".
- When the boys get defensive after an advertisement is thrown into their room, the face and stance that Jyushimatsu makes is reminiscent to Matsutaro of the sports manga Notari Matsutaro.
"We Got Sick"/"Todomatsu's Line"/"Choromatsu-sensei"
- Ichimatsu playing the role of "Dr. Ichimatsu", complete with makeshift cell and restraints. He even calls Choromatsu "Choroice" during the segment.
"Interview"/"Girlymatsu-san 2"/"The Life of Chibita's Flower"
- Chibita wears a Conan suit at one point.
- At the stop the girls go to, the centerpiece statue looks suspiciously like the Neo Armstrong Jet Cyclone Armstrong Canon.
"Matsuno Matsunan"/"The Ichimatsu Incident"
- "Matsuno Matsunan" is one large one to Fist of the North Star, with a bit of Mad Max thrown in for good measure.
- The "Jyushimatsu Pan" segment is an obvious parody of Peter Pan.
- The scene where Jyushimatsu throws Karamatsu and rides on his back◊ harks back to when Tao Pai Pai did similar, minus the second person.
- The name of the race alone alone should evoke a famous racing game series in your head. The brothers even throw red (crab) shells at Osomatsu during the race!
- From the announcer to the sabotage, the whole thing felt like a Wacky Races episode.
- When Iyami takes over the Super Flag, one notices that Hatabou is chained to the head of the vehicle with a metal mouthpiece clamped over his head.
- The title card◊ for Ichimatsu-san has Ichimatsu making a similar pose to the title character◊ of Ikkyu-san.
- Jyuushimatsu's delinquent form has a hat similar to Jotaro's. Fitting, seeing as they share a voice actor.
- The "Mahjong" segment got a couple from Akagi and popular mahjong manga Naki no Ryuu.
- This episode is one to Drunken Master.
- One can spot a Justaway and Elizabeth in the background.
- The preview has a mention of Kimagure Karamatsu Road.
"Osomatsu-san, such as It Was"
- Karamatsu strikes Johnathan Joestar's iconic pose, as well as the victory pose of Usain Bolt.
- The episode also features a few references to goings-on within Japanese baseball, like Osomatsu and Choromatsu performing the "MaeKen dance" (named after Kenta Maeda, a baseballer who does it to stretch his shoulders). It can be watched in the beginning of this clip.
- The episode's climax is heavily reminiscent of Gurren Lagann, especially with the brothers' declaration that "what's impossible is impossible", an apparent reference to the show's theme of doing the impossible.
- The opening shows the brothers parachuting Balloon Fight-style.
- The end credits has the brothers resemble pegs sitting in a car, as in Game of Life.
- Popular!Todomatsu's chubby body bears a resemblance to Dr. Eggman's.
- "Proper" Choromatsu and Totoko look like they came straight out of Saber Marionette J. They also claim to have switched bodies during their training, which Karamatsu compliments them on saying it will net them millions of yen.
- "Proper" Ichimatsu looks like a cross between a classic Marvel hero and a character straight out of a Filmation cartoon.
- A couple of times, the sextuplets cry out the phrase "Koredeiinoda!", the catchphrase of Tensai Bakabon's Papa, from Fujio Akatsuka's other most famous work.
- "Synthesis" is one giant Shout-Out to the Shin Megami Tensei franchise. The music in the skit invokes the theme of the Castle of Shadows, there's a Jack doll in the skit, and every time they fuse they say "kongoyomo yoroshiku" ("please take care of me from now on"), a phrase commonly said after MegaTen fusing.
"The Eitarou Family/Give Them Back"
- For one piece of merchandise, Jyushimatsu and the other sextuplets were put in Butler costumes. Jyushimatsu's pose in particular matched one demon butler's pose from a volume cover. Another Actor Allusion, as Daisuke Ono also voiced Sebastian.
- The Osomatsu Party mobile phone app has a card featuring the boys having a paint fight, complete with water guns as the weapons and ink tanks strapped to Jyushimatsu's back. Choromatsu even wears a beanie similar to the in-game Bobble Hat.