Haruka Suzushiro from the Mai-HiME manga, apparently feels that girls having relations with other girls is wrong. Although in her Lotus-Eater Machine dream, she rules the school and all women serve her naked. Especially her rival Shizuru, who wears a leather dog collar and is made to get down on hands and knees so Haruka can use her as a nude bench (note that Yukino, her childhood friend who honestly has a crush on her, is exempt from this treatment). How does Haruka get out of the dream? She refuses to accept that she could ever be that happy.
In the anime version, Natsuki Kuga fits this trope, though she isn't confirmed to be gay until one of the art books. She's the perfect stereotype of a biker dyke (if perhaps a fair bit more attractive than per the stereotype), and Mai mentions that her lack of interest in any men has most of the school thinking she's gay. Natsuki's reaction to this is a mix of surprise and bluster, though she never exactly denies it.
Shibuya Yuuri of Kyo Kara Maoh is raising a daughter with his beautiful malefiance whom he shares a bed with every night in a world where same-sex marriage is taken for granted. He still considers himself straight and conveniently "forgets" that he's engaged on several occasions. A stunning young guy in season three basically plays the Damsel in Distress card hard in order to gull Yuuri into being used in war. Works really well, if not exactly sexually, playing on Yuuri liking to be the hero, and if Wolfram were willing to do this he might actually get somewhere. But he won't, because he's proud and lacks the subtlety to be devious.
In Azumanga Daioh, it's dead obvious that Kaorin has the hots for Sakaki, although she tries to play it off. It gets a massive Lampshade Hanging from Osaka in the 10th anniversary comics (see the page pic).
Magical Girl Lyrical Nanoha: While there are no openly lesbian characters, Rainbows are straighter than Subaru, who has a long-standing friendship with the Tsundere Teana, serving together in the Bureau for four years before opportunities for their dream positions presented themselves, and with Subaru almost constantly e-mailing Teana afterward. Subaru also enjoys fondling Teana's breasts while she's asleep, and glomps Teana when seeing her for the first time in a year and a half.
Ryo MacLean in FAKE. From the get-go, everyone assumes he has a thing for his new partner Dee Laytner except for him.
When Wiccan of the Young Avengers came out to his parents, their response was to say that they always knew and welcome his boyfriend to the family. The problem is he was trying to reveal that he and his boyfriend were superheroes.
Lt. Cecil "Doubtful" Milk in Adventures in the Rifle Brigade, who takes the Ambiguous out of Ambiguously Gay. He can't seem to keep a girlfriend, is hip to the latest fashions, and despite being the sole survivor of several hot engagements the sternest word he's ever used is "ghastly". He repeatedly fakes fatal wounds, using his "last request" to goad Captain Darcy into performing romantic gestures towards him; everyone, him included, sees these as hilarious pranks and nothing more. Near the end of the first miniseries he confesses that he wants to be Darcy's bride, with the both of them later agreeing that he had gone temporarily insane from stress. When his uncle tries to specifically broach the subject, Doubtful doesn't seem to be aware that there's such a thing as being gay.
Also, his last name was Milk. Like... Harvey Milk, the first openly gay man to be elected to public office in California.
Played straight in Ultra: Seven Days; Cowgirl's friends often tease her about her boyfriend's obvious (and strongly denied) homosexuality, and the fact that he is clearly engaging in a homosexual affair with his sidekick. It's subverted, however, in that the fact that Cowgirl herself also turns out to be gay and in the closet completely floors them... despite the fact that Cowgirl herself is in many ways rather butch.
L: Oh, my apologies, I forgot that you're the sexual scourge of womankind. You obviously only have sex with me because you roll over in your sleep and misjudge the distance. Maybe you're sleepwalking... or maybe the term, 'sleepfucking', would be more appropriate. Maybe you're completely unaware of what you're doing.
In Fever Dreams Light doesn't like to think of himself as gay even though he's only ever enjoyed having sex with men. He is forced to come out in order to convince Rem that a relationship with Misawould never work.
Marik: I'm not gay! [Bakura laughs] What? What's so funny?
Bakura: Come on, Marik, we all know!
Marik: Know what?
Rex: Uh, heheh, yeah, we know.
Weevil: Heheh, yeah, we know.
Pegasus: I definitely know!
Marik: Know what? What the hell does everybody know?
Bakura: Marik, I believe it's time you came out of the closet.
Marik: Oh, what, just because a guy likes to dress effeminately and hang around with another extremely attractive man and read yaoi and flaunt his gorgeous abs and stroke a phallic symbol suggestively in every other scene, that automatically makes him gay?!
In the My Little Pony: Friendship Is Magic fanfic The Model Caretaker, Rarity becomes rather convinced that Fluttershy's closet is very translucent if not outright transparent after an openly bisexual Fleur de Lis comments on her flanks when she thinks she's out of earshot and she shows all the signs of arousal you can expect from a Pegasus (while internally screaming at her body for betraying her). In the next chapter, when Rarity suggests that she go on a date with Fleur, she yells that she's not a fillyfooler. While Fleur doesn't say as much, it is implied that she also thinks Fluttershy is gay (she eventually comes out as bi).
Pretty much the entire premise of In And Out, to the point that the protagonist's buddies bring Barbra Streisand movies to his bachelor party.
Wally Terzinsky in The Kids in the Hall: Brain Candy. Despite his tendencies to masturbate to gay porn, dream about gay sex, and get arrested naked at gay rest stops, it takes wonder-drug Gleamonex to get him to finally realize that he's gay.
Lance Delune in The Ladies Man, the leader of "Victims of the Smiling Ass", who likes Greco-Roman wrestling a little too much.
Captain Shakespeare, in Stardust, maintains a reputation as a fearsome pirate captain, among his crew as well as the rest of the populace, whilst owning an extensive closet for crossdressing in the privacy of his cabin. When he's found out, the crew admits that they always knew, but do not particularly mind.
This one's an interesting semi-subversion; the crew knows, but outsiders evidently remains in the dark.
As Straight Gay as Jack and Ennis of Brokeback Mountain are, they can barely keep their hands off each other when they're together - Ennis' wife Alma finds out about them when she sees them kissing, outside, in broad daylight. Sure, they're in love, but this is 1960s Wyoming.
Jay of the View Askewniverse's infamous response to being accused of fantasizing about other men during masturbation: "Dude, not all the time!" Among many other incidents, including Silent Bob breaking his silence in one of the deleted scenes of Clerks II to accuse him of being "a deeply-repressed gay man". Word Of God is that the character is actually closet bi.
Jay: You know, Silent Bob, you're a rude motherfucker, but you're cute as hell. I could go down on you, suckle you, line up a couple other guys and start making like a circus seal. (kneels down and starts pantomiming this) What the hell, fucking faggot? I hate guys. I love women!
Megan in But I'm a Cheerleader! fits this trope perfectly. She never suspected she was gay and strenuously argues the point when confronted about it, saying that she has a boyfriend she's been going out with for two years. When asked if they've had sex, she says she's a Christian. Another character responds, "It's really easy to be a prude when you're not attracted to him, isn't it?"
Inverted in the very same film by having one of the lesbians (the Butchest one, at that) come out as straight.
Sorta paralleling the previous example, the main character of Saved lives in a heavily conservative Christian town and believes her figure skating boyfriend is straight. Once she suspects he's gay, she tries to cure him with sex and winds up pregnant, triggering the main plot of the movie.
"Gay-in-denial Mob tough guy" is pretty much the whole character of Corky's brother Peter in Corky Romano. Even the FBI knows — "latent homosexual" is the core of their profile on him.
The officious and cruel prefect Denson in Lindsay Anderson's if..... "All this homosexual flirtatiousness — so adolescent", while he looks longingly at blond junior boy Bobby Philips.
"Marc, your hair? It's blue. And you have a poster of Celine Dion on your wall."
Possibly played with in The Campaign, in which Zack Galifianakis's character, Marty Huggins, is protrayed as speaking and walking effeminately, often accompanied by his two adorable pugs, who he dotes over more than his own children. His relationship with his wife comes off far more as an affectionate friendship than a loving marriage (she, in fact, proposed to him, six times, before he said yes), and he seems to have no difficulty at all ignoring her to focus on his Senate race. In fact, she grows so lonely that it takes little to no persuasion for her to be seduced by his political rival. However, none of the other characters even act as if they suspect that he's closeted, even when it would be politically advantageous to them to call him out on it, and he seems genuinely hurt by what his wife does.
In Mary Renault's The Charioteer, Andrew Raynes is gay and in love with his male best friend. This is obvious to the friend, who's also gay, and to an older guy, gay as well, who acts as a father figure to Andrew. Andrew, however, has no idea, though sometimes he wonders: "This doesn't seem very — very sensible. Other people aren't like this...It makes me feel, in a way, jealous, without knowing what of...Things happen that one can't completely...the feeling of being different..." He does eventually realise, and writes in a letter, "Often before when I have been fond of people I have got somehow caught up in it all round; but I am such an average person, it must be quite common I thought." Given that Andrew is nineteen, that this is England in 1940, that his rigid religious beliefs declare homosexual sex wrong and that his only previous contact with homosexuality has been seeing a boy at his school who "used to bully the little boys, and terrify them into doing what he wanted" get expelled, it's not so surprising that he hasn't got things figured out.
Live Action TV
In the first season of The L Word, Dana and her friends all know that she's gay, but she keeps up a Transparent ClosetMasquerade in front of everyone else, dragging a Beard with her to all of her social functions, and so forth.
Tobias in Arrested Development, who has a habit of accidentally making every second or third sentence he says a homosexual innuendo. He's also shown attraction to Lindsay on a few occasions, making him Ambiguously Bi. The irony here is that Lindsay's actress is gay, while Tobais's actor is not.
There's also Barry Zuckercorn, whose frequent homophobic remarks are contrasted with his penchant for hanging out at rest stops and taste for Transvestite hookers.
Barry: Last time they were balls. I really wish they were balls.
... and Gil in Frasier. There was one episode where he was talking about him and his wife wanting to lose weight in the New Year, so he'd baked "motivational" muscular gingerbread men. The problem was he couldn't stop eating them...
Gil: This is my last little man, I promise. Oh, Gil, who are you kidding? Frasier: No-one, Gil.
Stephen Colbert's right-wing persona, in a perfect satire, indicates regularly that he's attracted to men while vigorously denying it, and the character's cartoon features a hero modeled after himself who regularly hops into bed with women, all of whom say "You've obviously had hundreds of girlfriends" and just about all of whom turn out to actually be man-eating monsters. In one episode, they show a diagram of his brain; one section is labeled "repressed homosexual urges".
Six Feet Under had Father Jack (not to be confused with the Father Ted character of the same name), who initially was portrayed as a slightly effeminate, fairly liberal, gay-friendly priest. Audience members could be forgiven for expecting him to be outed at some point in the series, but when David suggested Jack might be gay (as he had assumed), he denied it. Still, comments he made in one of his later appearances suggested that perhaps the closet had been transparent all along, and that he had since vacated it.
Maybe??? He was caught renting gay porn...
Devon Banks, Jack's corporate rival on 30 Rock, claims to have been "cured" of his homosexuality, but still seems aroused by pretty much anything with a penis. His closet involves getting engaged to the CEO's daughter, by all appearances mentally retarded.
Played with, in that he is not closeted because of any of the usual reasons, but rather, is faking his heterosexuality in order to inherit the company through said engagement. He has also admitted that he is gay to Jack, because he knows well enough that Jack can't do anything about it.
Done for a dramatic reveal in the pilot of Kings. Crown Prince Jack Benjamin tries to hide behind the facade of a party-hard, womanizing career officer, but when he confronts his father about not being appreciated for his military efforts, Silas rips into Jack about his secret, revealing that he's known for a long time. Jack's reaction makes it clear that he's been terrified of the king finding out for a long while.
Jack: Is it my reputation, the 'party prince,' is that it? None of that matters - dad, it's not who I am—
Silas: Oh, if only it was. What would I give for a playboy who couldn't keep it in his pants, who runs through women? But what I have is a son who shows no interest in them. Oh, you thought I didn't know? I've been keeping pictures of our family out of the free press for years. What you do at night with your boys, after your show of skirt-chasing, is a disgrace.
Andrew Wells. Never actually confirmed, however heavily, heavily implied that not only is Andrew gay, he's in love with Warren. Issue 3 of Season 8 has him saying he's bored since all the Slayers (all female, all very fit) want to do is play strip poker. Combine that with some of his actions in his appearances in Season 5 of Angel and a flashback of him and Jonathan sharing a bed in Mexico in Season 7 and it's safe to say he's gay.
One could argue that it is confirmed that Andrew is openly gay, especially by the last season. Perhaps he was closeted at first; after being abandoned by Warren, Andrew wails "He never really loved...hanging out with us", obviously switching from saying "he never really loved me". But in an episode well into season 7, Xander declares that he is "going gay" because of how many of his female dates have turned out to be demons trying to kill him. He explicitly looks at Andrew for support, telling him "I'm mentally undressing Scott Bakula right now, how's that?" to which Andrew whistfully replies "Aaaah, Captain Archer!"
At first Willow and Tara are this to the viewers, as tons of implications are dished out long before they outright say anything. The rest of the cast who don't interact with the two of them together much are far more surprised to find out. Lampshaded when Faith in Buffy's body figures it out within minutes of meeting them together.
Jen has a date like this in The IT Crowd episode "Work Outing".
Also in Black Books where Fran has a date with a man who was in the navy before he became an antiques dealer, phones his mother five times a day, enjoys Shirley Bassey and thinks the linking factor between Elton John, Ian McKellen and Jean-Paul Gautier is that 'they're all fabulous!'. Writer Graham Linehan seems to enjoy this trope.
Salvatore Romano on Mad Men is an interesting case. The character throws out just about every 'gay' marker imaginable, and is easily recognized as such by the audience, but because the show is set in the early 1960s, almost none of his straight colleagues recognize this. His facade is so effective that he's been married for at least two years and his wife barely noticed anything; the only one of his colleagues who is aware of Sal's sexuality is Don Draper, who only knows because he saw Sal half-naked with a bellhop while escaping a fire at a Baltimore hotel. Don keeps the secret; he's not the judging type, and has a secret of his own anyway.
Tom and Crow on MST3K. Debatable though. In ten years, Crow is the one who tends to act rather camp, particularly in the Comedy Central era, and is the Bot on record as having had an erotic dream about Tom and the one who went all giggly at the thought of touching Robert Redford. In contrast, Tom... is curvy and has a good singing voice. As with everything in MST3K continuity, though, Rule of Funny in in full effect.
Played with in one of the Joel-era episodes. Tom and Crow are discussing how various celebrities "were one", and Joel wondered what they were talking about. Crow tried to work up the courage to tell Joel, but fainted. Tom finally came out and admitted it:
Tom: "Joel, Crow and I ... are robots. There, I said it."
Joel: "Oh. Well, I knew that."
Tom: "What? How?!"
Joel: [smirking to the camera] "It's more than a little obvious."
Kurt Hummel on Glee, at the beginning of the show. When he came out to his dad, his dad told him he knew since Kurt was 3 years old.
His best friend wanted to date him in the beginning, not knowing he was gay.
To an extent, Santana was as well, though mainly just to her friends. Her habit of very quickly dismissing or explaining away or outright ignoring her relationship with Brittany.
Robin in The Smoking Room, to a tragic (well, tragicomic) extent: by the time everyone finally tells him that they already know and they don't care, the object of his obsessive crush, Ben-from-the-mailroom, has already come out, dumped his fiancee, and started dating another guy.
Kenny in The War At Home. He has a crush on his straight friend Larry, the joke being that everybody recognises his blatantly gay characteristics apart from Larry himself.
In Torchwood: Miracle Day, the steward on a flight being taken by the main characters is repeatedly assumed to be gay, despite his protests. Eventually, he is worn down enough to admit "it was only one time."
Wyckyd Sceptre, a fictional band in Mr Show. They completely fail to comprehend the fact that they are gay, despite being confronted with video of themselves having gay sex.
Brad Bottig, Sue's off-again, on-again boyfriend on The Middle. Brad and Sue seem to be the only two people unaware that Brad is gay.
In a Mad TV sketch, Stevie has a Coming Out Story with his friends and family, despite the fact that they've already know since he's spend three Halloweens as Wonder Woman and when he played Cowboys and Indians with his brother, he was as the Cop in the George Micheal video. Surprisingly, the only one was actually shocked was his Lover, Sebastien.
Roy Cohn in Angels In America does this right to the face of the doctor who diagnoses him with AIDS.
Roy: I don't want you to be impressed. I want you to understand. This is not sophistry. And this is not hypocrisy. This is reality. I have sex with men. But unlike nearly every other man of whom this is true, I bring the guy I'm screwing to the White House and President Reagan smiles at us and shakes his hand. Because what I am is defined entirely by who I am. Roy Cohn is not a homosexual. Roy Cohn is a heterosexual man, Henry, who fucks around with guys.
The leader of the missionaries in The Book of Mormon is this played for laughs, claiming that he managed to take his gayness and "Turn it Off." He obviously didn't.
Thomas MacLaine of Deadly Premonition is an unsubtly effeminate Shrinking Violet of a man. Of course, that's not so much the surprise as to who he happens to be involved with. That and the fact that he's not only a homosexual, but a transvestite.
In Dont Take It Personally Babe It Just Aint Your Story, Akira discovers, much to his embarrasment, that everybody in his class knew about his homosexuality before he even decided to come out of the closet, and they aren't even shocked or interested. Even worse, his own mother reaction accounts to posting the equivalent of "lol finally" in the message he used to officcialy come out.
Not really, the only one who ever guessed it was the also gay Justin. The only reason that everyone knew was that because Susan messed up and told everyone about it. However it is implied that this trope will come into play soon, as she recently had a very obvious and very public argument with her girlfriend.
Sarah finds out while she and Grace are hiding behind the couch at the birthday party, intending to surprise Susan and Nanase. Grace was unsurprised, saying that she thought it was obvious that Nanase and Ellen had feelings for each other. Also, Susan had started to pick up on these feelings before Nanase had, working it out when Nanase mentions Ellen's V5 pheromones which Ellen didn't have anymore. A recent comic reveals that she'd suspected her of being gay since sophomore year.
Ethan in Shortpacked!! A bit strange, since his personal revelation comes the day after apparently great sex with a hot woman.
Ethan's an interesting example, because while Amber kept telling Robin that Ethan was gay, neither of them actually knew that at all. Amber made it up to get Robin to give up on Ethan, and when Robin tells Ethan that he's supposed to be gay, that's when the epiphany hits him. Given that Ethan's a Straight Gay, this is more of an Accidental Truth on Amber's part than a Transparent Closet.
Sara from Penny and Aggie does not realize she is gay and aggressively accuses nearly everyone else around her of being a closeted homosexual (despite having fantasies about Lindsay Lohan) until she kisses Marshall and discovers/admits to herself that she is gay.
Most of the cast of Misfile believe Emily is living in one of these, partly because Emily makes sure to constantly remind them that she isn't gay.
It should be noted that the "girl" she's attracted to is psychologically male, so the situation is... unique.
Due to this, debate rages on and off of the Misfile forums on whether Emily qualifies as straight, gay, bi, or just Ash-sexual.
Most of the cast is incorrect. The only two who seem to have even considered otherwise are Missi and Emily herself. For people to believe Ash as the lesbian is much more viable, unfortunately, the only person to realize that completely on her own is the niece of the devil.
Angela explains in Punch an' Pie how she came out as bi to her friends: "They knew before I did. There's nothing like a loud chorus of 'Christ, FINALLY' to take the wind out of your sails."
Keti from Footloose since An was revealed to be female, who still loudly denies having any feelings for her, despite the Luminescent Blush whenever they're in the same room, even as she's dragged her friends into tailing her on a cross-country foot trip into a pirate lair.
Inverted early on with Monette, although it didn't last forever.
Mecha Maid in Spinnerette's attraction to the title character is incredibly evident to everyone else but Spinnerette herself. When she finally gets the nerve to ask Mecha Maid whether or not she's attracted to her, Mecha Maid chooses to lie and tells her that their relationship is strictly friends.
Spinnerette doesn't buy it, though, and when she confronts her again, Mecha Maid finally admits it.
Mr. Garrison, in earlier episodes of South Park. Since then, Garrison's touched every single point of the GLBT spectrum: first being a man in denial, then a Camp Gay, transgender man-to-woman, Camp Lesbian, transgender woman-to-man, and back to Camp Gay (or possibly still attracted to women) again.
Xander Crews from Frisky Dingo. The huge gay porn collection and the posters of male celebrities all over his house are kind of a give-away, but he still insists that he's straight. To be fair, he does seem to like women, but a repressed attraction to men is pretty obvious, too; among other things, he pretty quickly turned to doing gay porn after losing his fortune.
The Larry 3000 on Time Squad, starting in the episode "Blackbeard, Warm Heart," in which Larry announces unashamedly to a pirate crew that people have called him a sissy for his entire life while he reclines in a lacy pink bunk bed, among other things. The closet became more and more transparent until it reached its peak in "Ex Marks the Spot," which centered around Larry trying to "win back" his time cop partner Tuddrussel after he thought Tuddrussel and his ex-wife Sheila were falling in love again. (This episode implied that Larry had had sex with Tuddrussel for the first time, so his anxiety ran especially high.)