* Like everything else they do, comic books (particularly those from {{Creator/Marvel|Comics}} and {{Creator/DC|Comics}}) tend to be pretty up and down when it comes to this. One storyline will explicitly state that the other version of heroes are simply limited to fictional comics, another will confirm that they all coexist with the same world, and in another, {{Alternate Universe}}s come into play. All in all, [[BellisariosMaxim most writers try not to stress over this too much]], as more often than not, the main objective is to either have [[LetsYouAndHimFight two heroes duke it out in a prize fight]] or simply deliver some cheap shot.
** It's widely established that Franchise/TheDCU and Franchise/MarvelUniverse exist in the same... Multiverse? Megaverse? Adjacent multiverses? Same something. They met on several occasions, and the universes even merged for a while in the early 90s.
*** There's even a gag during a Marvel VS. DC mini (prior to ComicBook/{{Amalgam|Universe}}) where a man walks into a toy/novelty store, as if he'd done so regularly before the universal collide, and asked where all the "X-Men Stuff" had gone. The clerk responded, "What's X-Men?" Maquettes of two [[WesternAnimation/PinkyAndTheBrain characters]] should tell you the universe in which this transpired.
** DC, prior to 1986, did this using Earth-2 and claiming that the Earth-1 characters had comics about the Earth-2 characters but not about themselves. This explanation worked for characters like TheFlash, but wouldn't make sense for someone like Franchise/{{Superman}}, where both versions had the same secret identity.
*** On Earth-1, they did reveal that there's "true crime" comics based on the adventures of Earth-1's Superman, Batman, etc. (based on newspaper accounts, etc.), alongside the fictional-to-them comics about the Earth-2 Flash, Green Lantern, etc.'s adventures.
*** A Franchise/{{Batman}} arc from the '80s involved Batman investigating the murder of a comic-book writer who worked on a Batman comic. At one point Bruce Wayne admits to himself, "I should have seen this coming." He mentioned that he couldn't risk copyrighting the Batman name without blowing the SecretIdentity. The in-universe Batman comic, interestingly enough, portrayed the Caped Crusader as a penitent bat-headed demon who came to Earth to send criminals to Hell Comicbook/GhostRider-style.
*** An issue of ''TheFlash'' shows that Irey West has a poster from the ''WesternAnimation/TeenTitans'' cartoon in her room. Ya know, the cartoon that had ''her dad'' as a guest star.
**** Though interestingly enough, the cartoon rarely if ever used the heroes' real names. So in theory, ''Teen Titans'' could absolutely be a TV show in the DCUniverse without jeopardizing the identities of the actual Titans.
** However, at least in the Franchise/MarvelUniverse, there is {{Canon}} evidence from comics such as ''ComicBook/SheHulk'' and ''Comicbook/FantasticFour'' that the exploits of the (in-universe) real live heroes are actually recorded in comics and sold to the general public. These comics (in the ''She-Hulk'' comics) are then used as evidence by lawyers defending and prosecuting super heroes and super villains. And, at least once, to save the world when all the characters had forgotten some hugely important fact or MacGuffin which they found out about by reading the comics. One wonders, though, if the comics published in-universe are the same as the RealLife ones, and the references to comics are infinitely recursive. But then one's head starts hurting.
*** Similarly, after his [[TheSilverAgeOfComicBooks Silver Age]] revival, Comicbook/CaptainAmerica ended up drawing his own comic book in-universe. Which is even more mind-bending; the superhero was drawing a comic book about his own adventures? Hard to know what's really true. Note that at the time, Cap's true identity as Steve Rogers was not publicly known, so the publisher had no idea he had Captain America drawing Captain America.
*** Marvel actually ''released'' a set of in-universe comics during a FifthWeekEvent in 2000. These were titled "Marvel[[color:red:s]] Comics" and how similar they were to the "real" superheroes varied -- the Fantastic Four licensed their comic officially and appeared in their real identities, but since nobody knows who Comicbook/{{Daredevil}} or Franchise/SpiderMan are, the in-universe comic fabricated origins for them.
*** The infinitely recursive references problem would only apply if heroes continued licensing their adventures to comic companies all the way up to the modern era, which they don't seem to do.
*** Creator/EdBrubaker's ''Comicbook/CaptainAmerica'' run revealed that the ''Captain America'' film serial from the 1940's exists in the Franchise/MarvelUniverse. There's a bit of FridgeBrilliance to this: in real life, the serial changed up Cap's origin and name so that his civilian identity was [[AdaptationNameChange Grant Gardner]] rather than Steve Rogers. Ergo, the serial could exist in the Marvel Universe without having jeopardized the real Cap's secret identity in any way.
* ''Superman'' # 411 established that the Julius Schwartz of Earth-1 went bankrupt after he unveiled Ultra-Man, Madame Miracle, Night Wizard, and Jet Jordan only to see the emergence of the Earth-1 Superman (as Superboy), the Batman, Wonder Woman, and the Flash (whether they meant the publication of Jay Garrick's adventures on Earth-1 or the emergence of Barry Allen remains unclear -- also, other stories established that the Shadow actually existed as part of Earth-1's past, so Night Wizard would have already seemed a tad redundant). Possibly, Madame Miracle explains how Wonder Woman seemingly appeared on the copy of ''All-Star Comics'' # 37 that Barry Allen had in ''Flash'' # 137; otherwise people on Earth-1 would have felt astonished when the Earth-1 Wonder Woman left Paradise Island to enter Man's World. (On a related note, no word ever appeared on what the people of Midway City, Michigan felt when someone dressed in a virtually identical costume to Hawkman emerged, and a museum curator named Carter Hall moved into town.) While the Earth-1 Julius Schwartz seemingly appeared as a gainfully employed staff member of the Earth-1 DC Comics in the ''Titans Crisis'' crossover, the ''Teen Titans Index'' # 5 notes that this represented a different bald, glasses wearing-staff member.
* In the UltimateMarvel universe, one issue of ''Comicbook/UltimateSpiderMan'' involved Spidey's exploits being filmed by Creator/SamRaimi to save money on CGI for a blockbuster movie starring Tobey Maguire.
** When Ultimate Spidey went to Raimi to ask him to stop, they just filmed him some more. The majority of the movie in the Ultimate universe was made up of real footage from a battle between Spidey and Dock Ock. Naturally, Peter doesn't see a dime from it and resents the movie, which ought to reflect poorly on Raimi and Maguire but it mainly comes off as RuleOfFunny.
*** For some reason Avi Arad was also on set, apparently as a creative consultant. How he got that job is never really explained.
** Marvel did another joke on this in ''Comicbook/{{Spider-Girl}}''; Mary Jane comments that Reilly Tyne (son of Spider-Man's clone Ben Reilly) looks sort of like Peter; Pete, on the other hand, thinks he looks more like Tobey Maguire.
** SelfDemonstrating/{{Deadpool}}, meanwhile, has mentioned on more than one occasion that he's seen the Spider-Man movies and knows that it's "doe-eyed Tobey Maguire" underneath the mask. But then, he is Deadpool, so maybe [[NoFourthWall he has seen the movie on the other side of the fourth wall]] or something.
** In one issue, Spider-Man says that he's got a little experience with impostors, "be they clones, robots, or Tobey Maguire."
*** SelfDemonstrating/{{Deadpool}} himself says in one issue that he looks like "RyanReynolds mixed with a Shar-Pei." No sign of the Shar-Pei, but who else would get the role when the live-action movie came out?
** In ''{{Ultimatum}}'', Peter's buddy Kong suggests that he and his friends go see ''Film/TheDarkKnight''.
** Also subverted in the UltimateMarvel universe: when discussing which actors should play the various members of the Ultimates, NickFury nominates Creator/SamuelLJackson for himself. This being an obvious meta-reference, as Marvel had based Ultimate Nick Fury's likeness on Jackson, with the agreement that they'd cast him for the movie version when the time came.
** Subverted in ''ComicBook/SupermanSecretIdentity'', where there are no superheroes, but ''Superman'' comics do exist -- they're, in fact, the reason Mr. and Mrs. Kent decided to name their perfectly human boy Clark. Then, after being constantly bullied about his nonexistent superpowers, he actually gets them, and the rest of the plot explores the differences between comics and "reality."
*** Superboy-Prime had a similar origin. His psychopathic behaviour in pursuit of [[TheSilverAgeOfComicBooks Silver Age]] values can be at least partly explained by the fact he still thinks of these people as fictional characters.
** A [[TheGoldenAgeOfComicBooks Golden Age]] ''Superman'' story had Clark taking Lois to the movies... where a Fleischer Brothers ''{{WesternAnimation/Superman|TheatricalCartoons}}'' cartoon was showing before the main feature. HilarityEnsues as Clark goes to great lengths to ensure that Lois is distracted every time his on-screen counterpart changes identities. The story ends with Clark and his on-screen counterpart winking at each other, even as he wonders who [[MaxAndDaveFleischer the Fleischer Brothers]] ''are'' and how they found out all they did.
** The ''World's Collide'' crossover, where the characters of DC Comics met the characters of MilestoneComics, had this since Marvel and DC were both fictional universes within the Milestone Universe. {{Icon}} expressed concern that he might not be strong enough to battle Superman, who he remembered from the original Christopher Reeves ''Film/{{Superman}}'' film.
** In an issue of ''BatmanAndTheOutsiders'', Salah programs Re-Mac with several basic forms, one of them including Creator/GeorgeClooney, which amuses Grace Choi and irritates her girlfriend Anissa. This brings up the question if the George Clooney of that universe did indeed star in ''Film/BatmanAndRobin'', and what Batman himself would make of that.
** Similar to the ''Ultimate Spider-Man'' example, an issue of ''[[Comicbook/HarleyQuinn Harley and Ivy]]'' had the title characters tying up and gagging two actors who were supposed to play Batman and The Joker in a movie. Before being gagged, the man portraying the Joker quoted some lines from ''Film/TheEmpireStrikesBack'', implying that he was Creator/MarkHamill. The same Mark Hamill who voiced the Joker in ''WesternAnimation/BatmanTheAnimatedSeries'', the show the comic was based on.
** Similarly, in ''ComicBook/ArkhamAsylumLivingHell'', Warren White notes that "Years from now, people will think Halliburton was the guy who made ''Film/EdwardScissorhands''." So, did Creator/TimBurton make ''Film/{{Batman}}'' and ''Film/BatmanReturns''?
* While maybe not textbook, ''Comicbook/{{Watchmen}}'' played with this a little bit. Creator/DCComics, the company that published the book, did once exist, but they stopped publishing after ''real'' superheroes emerged. To fill the publication vacuum, comics starring pirates became popular--hence, nobody notices the similarities between characters like Nite Owl and the Blue Beetle or Rorschach and TheQuestion.
** The ''TopTen'' universe plays around with this. With so many superheroes, comics about mundane people, such as accountants, are popular.
** ''Comicbook/{{Runaways}}'' mentions Franchise/TheDCU a few times, but it's implied they only exist as TV shows.
* ''ComicBook/AstroCity'' plays with this as well. Comic book publishers can either publish stories of fictional characters like Franchise/{{Batman}}, or secure licensing rights and publish the exploits of real superheroes. Since the heroes are real, authors and publishers are vulnerable to libel laws[[note]]however, masked testimony is allowed only in criminal cases, not civil ones, greatly limiting the ability of masked heroes to actually bring a lawsuit[[/note]], and comics are required to adhere to known facts and events.
** The story "Where the Action Is" details a comic publisher who publishes embellished exploits of "real life" heroes and villains, with increasingly dangerous results. First, the hero Crackerjack shows up to complain about lack of royalty payments (the publisher puts him off with fast talk and HollywoodAccounting); then, the heroine Nightingale threatens him for insinuating that she and her partner are a lesbian couple (he brazens it out, noting that she'd have to reveal her {{secret identity}} in order to sue him). Finally the villain Glowworm corners the publisher at a convention and almost kills him for portraying him as a white supremacist (Glowworm has a radioactive sheen -- underneath it, as he puts it, "[[YouKnowImBlackRight You know what color]] I ''used'' to be?"). After the last threat, he decides to start a line of "cosmic" (alien/otherworldly) heroes and villains, since they are too [[AscendToAHigherPlaneOfExistence above mortal concerns]] to register complaints. [[spoiler:The building gets vaporized one morning several months later.]]
* In his WesternAnimation/DonaldDuck comic stories, Creator/DonRosa prefers to think of MickeyMouse and other non-Duck cartoon characters as the fictional characters within the fiction, and the Duck characters as the "real" people. This becomes weird when you take into account that Donald was also Mickey's co-star in animation.
** Don Rosa had also played with the idea of writing a story wherein Donald goes to Hollywood and meets Mickey and Goofy, world-famous actors who stars in a film-franchise as [[TheDanza characters named after themselves]] (Donald would [[YourCostumeNeedsWork refuse to believe that it actually was them]]).
** WesternAnimation/DuckTales comics also exist inside his universe. He's mentioned that he likes to think of them as unlicensed fabricated adventures based on the colourful character of the city's biggest celebrity, Scrooge [=McDuck=], and would like to make a comic about him facing the copyright issues involved to prevent the comic's sale, but Creator/{{Disney}} hasn't at least yet relented to allowing its major animated series to be treated like a pirate release, even inside a comic.
* In a case of metafiction meets RealLife, the Disney corporation sued Marvel Comics, stating that the Marvel character Comicbook/HowardTheDuck bore too much of a resemblance to Donald Duck, and violated their trademark. Marvel then redesigned future artwork of Howard, changing his overall appearance. But most importantly, Howard would always be drawn ''wearing pants'', apparently because Donald now owned exclusive rights to all depictions of talking duck nudity! In the Marvel comic, Howard would often complain about being forced to wear pants, because he was personally sued by some undisclosed powerful corporation. Due to the Disney/Marvel merger, Howard can presumably go pantsless once again.
* Averted (or arguably lampshaded) in the original ''Worlds Collide'' crossover between the DCU and the [[MilestoneComics Milestone Universe]]. The Milestone Universe has Superman comics, so when the Milestone heroes get cosmically shunted to the DCU, they know Superman's secret identity (and originally assume he's just some yutz dressed up like Superman). The more recent ''When Worlds Collide'' established that the two universes have since merged, presumably wiping out the Milestone heroes' inappropriate memories.
* Most screen adaptations of Superman's origin -- at least those that don't try to incorporate the rest of the DCU as well -- act on the assumption that the whole concept of a super-hero does not yet exist in this world, not even in fictional media.
** However, in the 1978 Christopher Reeve film, Ned Beatty has a rolled copy of Comicbook/TheMightyThor in his back pocket.
** Prior to the incorporation of the DCU in ''Series/{{Smallville}}'', SelfDemonstrating/LexLuthor was an avid collector of comic books, his favorite being a Superhero named Warrior Angel, which started out as vaguely Superman, and then evolved into the ''Smallville'' equivalent of [[Comicbook/{{Shazam}} Captain Marvel]]. It also plays with the above statement slightly: Clark might not be the first Superhero, but he has gotten the most attention.
* ''Comicbook/FreddyVsJasonVsAsh'' pits Ash Williams of ''Franchise/EvilDead'' against Freddy Krueger. ''The Evil Dead'' is seen playing on a TV in the original ''Film/ANightmareOnElmStreet1984''.
* As an in-joke to Creator/RobertDowneyJr playing the live-action Film/IronMan role, ''Comicbook/IronMan vs Whiplash'' has Tony Stark check into a hotel and pay an exorbitant amount to not have any questions asked (since he has been accused of a massacre). One of the hotel staff says he knows who Tony really is.. and guesses Robert Downy Junior
-->'''Stark:''' Guilty as charged..
* Non-actor version: One SelfDemonstrating/{{Deadpool}} comic [[Memes/{{Comics}} famously]] features a scene where he incites {{Wolverine}} to violence by saying to Kitty Pride "Speaking of games, ever played ''Franchise/StreetFighter''?" and then {{Shoryuken}}-ing her in the face. Then Udon delivered a ShoutOut to that scene in their ''Comicbook/StreetFighter'' comic, where Ryu says "Speaking of comics, ever read ''Deadpool''?" and then Shoryukens Sagat.
** This carries over to the video game MarvelVsCapcom3 which has both Deadpool and Ryu. Not only does he still use the Shoryuken, he explicitly recognizes the Capcom cast as originating from Video Games, stating he loves ''VideoGame/StreetFighter'' whenever he fights a charater from those games, among other things (though they never seem to react). Either Deadpool is merely BreakingTheFourthWall again, or the capcom characters actually do have video games in the marvel universe, as the plot involves a scheme between villains of both worlds to merge them into one Earth. No word on whether Marvel comics exist in the Capcom world, however.
*** Deadpool has apparently played the ''Videogame/XMen'' arcade game, since he will taunt Magneto with [[AscendedMeme "Welcome to die!"]]
* An issue of [[ComicBook/GIJoeARealAmericanHeroMarvel G.I. Joe: Special Missions]] has a child receiving a toy of the {{Franchise/Transformer|s}} Jetfire. Strangely, Transformers and GI Joe shared the same continuity, and Jetfire even appeared in the GI Joe vs The Transformers miniseries.
* An early issue of Creator/GrantMorrison's ''Comicbook/AnimalMan'' run has Buddy listening to Music/{{REM}}'s "Superman" on his Walkman about 10 seconds after having a conversation with Franchise/{{Superman}} himself, making you wonder what the song's lyrics look like in a world where Superman is a well-known celebrity rather than a fictional character.
* Howard Wolowitz and his friends from ''TheBigBangTheory'' make a cameo appearance in a 2009 issue of ''Power Girl''. One wonders if the gang own that particular comic book...