A number of people have been identified as (or implied to be) lesbian, gay, bisexual or transgender (commonly abbreviated LGBT).
So far, no characters have been described as asexual or demisexual.
Kang and Kodos are gender ambiguous. While Kang is usually shown as male (although he may be a hermaphrodite), Kodos’ gender is uncertain: Kodos has a male voice and is called male in “E.T. Go Home”, yet is also called “sister” and wears female clothing in Tapped Out. However, Kamala is explicitly shown as female. It could also be possible that Kodos was referred to as "sister" for comic purposes.
- Patty Bouvier - Almost married Veronica. However, Veronica was actually a man named Leslie, so the wedding was called off. However, Patty has been shown with men, i.e. Principal Skinner, although this was before she was established as homosexual. In Treehouse of Horror III, she says “there goes the last lingering thread of my heterosexuality” after seeing Homer naked, but this is a non-canon episode and could simply be given the line for comic effect.
Hinted to be Lesbian
- Martha - hinted as being attracted to the assistant librarian.
- Librarian - hinted as being attracted to Martha.
- Megan Matheson - Admitted to having a wife.
Openly Gay Characters
- Comic Book Gay - Comic Book Guy's gay cousin. He likes "certain kinds" of comic books.
- John - A nostalgia store owner who befriends the Simpson family. He is voiced by John Waters who is openly gay in real life.
- Roscoe - Manager of the Ajax Steel Mill. He and his workers are all gay, and at breaks, they turn the mill into a gay nightclub.
- J&J Construction Contractor - A builder who was employed to remodel the Simpsons' kitchen after Homer's failed attempts.
- Grady and Julio - A gay couple that Homer roomed with; they later broke up. Grady is voiced by comedian and actor Scott Thompson who is openly gay in real life. Hank Azaria (voice of Julio) previously used the same voice for another gay character named Agador Spartacus in the 1996 comedy film titled The Birdcage. This reference is further grounded in the episode's aptly parodied title, The Burns Cage.
- Thad - Marries Julio (with Homer as the officiant) subsequent to Julio's and Grady's breakup.
- Grizzly Shawn - Becomes interested with Moe.
- Dewey Largo - It was first assumed in See Homer Run when he claimed that he and Waylon Smithers were carpooling. In Flaming Moe, he announces to his music class that he is running away with the love of his life, who is a man. He also has an exaggerated lisp.
- Waylon Smithers - There are numerous references to Smithers' orientation (or at least his fixation on Mr. Burns) and his efforts to keep it a secret. However, a blatant example occurs when Smithers boots up his home computer and an animation of Mr. Burns appears, saying (in obviously cobbled-together sound clips), "Hello, Smithers. You're quite good at turning me on." Smithers then says to Lisa (who was standing behind him), "Um, you should probably just ignore that." Smithers was first shown to be openly gay in Flaming Moe, when he helps reopen Moe's tavern as a gay bar. Smithers comes out in The Burns Cage.
- Dewey - An ex-boyfriend of Dewey Largo.
- Elton John - He is openly gay in real life and has been married to Canadian filmmaker David Furnish since 2005.
- Philip Hefflin - A photographer who was interested in Abraham Simpson and claims that women disgust him.
In the Closet
- Unnamed Latino Man - When he saw Homer's graffiti tag of "El Homo", he said, "If only I had your courage, Señor."
- Unnamed smoking man - Moe tried to steal his watches, but when the man noticed him, Moe said that he had been just coming on to him. The man took Moe's hand and said that they could go back to his place.
- Raoul - Women disgust him and becomes interested with Abraham Simpson.
- Stuart - A close friend to Waylon Smithers.
- Gay Colonel - Colonel who dates with Hans Moleman.
- Patty Bouvier - Prior to the episode There's Something About Marrying where she comes out as a lesbian, she was in the closet and celibate by personal choice. She briefly tried to date Seymour Skinner.
Hinted to be Homosexual
- Rod and Todd Flanders - Ned Flanders gave Bart Simpson money for not outing them in Bart to the Future, they had mustaches and were seen refurbishing furniture in denim shorts and white sleeveless shirts. Also, both brothers have been shown to exhibit stereotypically gay behavior, such as holding hands while skipping. Also, one of them shouted to Ned that Marge “made me gay”, which resulted in Marge covering for him, due to Ned’s anti-gay viewpoints. But this was just Bart making Rod say this, as he told him it means that you used to be afraid, but now you're not.
- Karl - Kissed Homer on the lips after stating that his mom taught him to never kiss a fool. However, it should be noted that Karl is implied to be of German origin, and men kissing men doesn't necessarily equate to homosexuality as much as just respect in some European countries, but generally not on the lips, rather on the cheek. Karl also patted Homer on the behind after giving him a pep talk, but in the context of the situation, it could easily be considered a comradely gesture rather than an affectionate one.
- Llewellyn Sinclair - Is seen in the crowd of gays.
- Private Burns - in the level Medal of Homer, shortly after Private Burns taunts Sergeant Abraham Simpson by saying that he'll have to kiss him after dodging his attack, Abraham Simpson, when going for a second pass, refers to Burns as, among other things, a "nancy-boy" (a slang term for a homosexual). However, this is non-canon.
- Leprechauns - two of them held hands at a St. Patrick’s Day festival. However, one of them married a gypsy woman in “Hex and the City”.
- The Yes Guy - Although little is known about this character, he possesses a very eccentric and flamboyant personality. However, his speech impediment is due to a stroke.
- Lady Gaga - She is openly bisexual in real life (which is hinted in the hit single "Poker Face") and even kisses Marge Simpson in Lisa Goes Gaga, much to Marge's surprise. However, Marge is straight as far as we know.
- Rainier Wolfcastle - Openly bisexual since he has his early gay porn films located within his bedroom. 
- Verity Heathbar - Leaves her husband Charles for Patty, who says that they were brought together by their hatred of Homer.Patty has never had a confirmed marriage yet, however.
Hinted to be Bisexual
- Barney Gumble - He complains when crowded in a closed bomb shelter that someone is touching him, but he's okay with it when he learns it was Principal Skinner. However, he has had several girlfriends before, like Daria and Kako. His drunkenness could also be a cause of this.
- Duffman - Slept with Titania, who was competing in a bartending contest that he was judging. However, Bart mentions that Duffman is supposedly in a long-term gay relationship after seeing him dining with Booberella. He is later in a relationship with Grady. It should be noted, however, that there are several different actors portraying Duffman, and not all of them necessarily have the same sexual orientation. Also, some of the actors are now dead.
- The Sea Captain - Apu delivers pornographic magazines to keep the Sea Captain's crew from resorting to situational homosexuality for about ten minutes, at least. However, the Captain is also seen taking pictures of Selma and Patty in the nude to cope with being out at sea.
- Santa's Little Helper - Intrigued by male dogs at the Springfield Gay Pride Parade. However, he mated with both She's the Fastest and Rosa Barks, both of whom were definitely female as both unions produced puppies.
- Ralph Wiggum - In The Simpsons Movie, he declares "I like men now!" after seeing Bart naked on a skateboard. However, Lisa Simpson was his first crush. It should be noted, though, that nothing Ralph says about himself is reliable, since his understanding of everything is questionable.
- Milhouse Van Houten - Noted as having "flamboyantly homosexual tendencies" by Dr. J. Loren Pyror, but has a long-standing crush on Lisa Simpson and has dated other girls.
- Martin Prince - Generally effeminate and was shown to have a crush on Ralph Wiggum at one point . Accused of being gay by Nelson and protests, "I'm not anything yet!"; has a male robot boyfriend in the future. On the other hand, he did have an attraction to Princess Kashmir on seeing Bart's photo of her dancing with Homer, even referring to it as being "quite exciting" and calling her a "sexy lady" when he asked Bart who she was. When he imagines himself as a basketball player in "Replaceable You" he is holding hands with both a male and female cheerleader.
- Lisa Simpson - In the episode "Holidays of Future Passed", a montage of photos were featured to show a glimpse of what’s to come for the Simpsons family. Lisa is shown intimately holding hands with two women in one photo, then with a different woman in another photo. She is later shown married to Milhouse Van Houten and having a child with him, and possibly marrying Ralph Wiggum. She has also dated several other boys. In the episode Gorgeous Grandpa, Homer was flipping through the reality shows to Lisa's disgust. However, when Homer and Lisa keep flipping through channels and sees a reality show on gay marriage she says 'Well' and thinks about it. Al Jean also teased that a future-set episode in Season 29 would feature Lisa ending up with a woman. However, Mr. Lisa's Opus is ambigious about it. The episode Bart to the Future contradicts this when a then 38-year-old Lisa campaigns and wins to become "the first straight female President" of the United States.
- Homer Simpson - He is married to Marge, but has also shown admiration towards men. In "Three Gays of the Condo", he was surprised when Karl kissed him. He also yelled out "Stupid Sexy Flanders" after being blinded by Flanders' sexy body in "Little Big Mom".
- Gil Gunderson - Although once married to Shirley Gunderson, he is shown in Tapped Out wearing a Pride outfit.
- The first, the second and the third of The Cool Moms - They all are married and have sons, but when Marge abandons the club, they start kissing and hugging each other.
- Shauna - She is implied to be bisexual as Dolph said that she invited 200 guys and 7 girls to make out with her via a SpringFace message.
- Sideshow Bob - In "The Italian Bob," he admits to "experimenting in college."
- Lenny Leonard - Despite having a girlfriend, he is hinted to be attracted to Carl.
- Carl Carlson - Despite having a wife, he is hinted to be attracted to Lenny.
- Hans Moleman - He sadly states that “nobody’s gay for Moleman”. However, he once dated Selma, so whether or not he is secretly gay or bisexual is up for debate.
- Moe Szyslak - He wanted to marry Gil Gunderson and pretend that he's a girl in "Pray Anything".
- Edna Krabappel - while she has dated many men and was married to Ned Flanders , in The Ned-liest Catch, it is revealed she dated Patty Bouvier once.
- Judge Constance Harm - Indicates that she was AMAB.
- Brunella Pommelhorst - She said she would come back to Springfield Elementary as a man, but then decided to not go through with the surgery and is still a woman.
- Stanlerina - She is Helen Lovejoy's cousin who was AMAB, but transitioned to female at some point in her life.
Hinted to be Transgender
- Helen Lovejoy - The Parson tells Reverend Timothy Lovejoy that he "remember[s] when [Helen Lovejoy] was Helen Schwartzbaum. In fact, I remember when she was Harold Schwartzbaum." This is very unlikely, due to her and Tim having a daughter together, as well as a flashback clearly depicting her as a little girl. She also has no masculine characteristics. However, there is nothing confirming that Jessica is not adopted in any way and Helen is shown to be very supportive of transgender people, despite being conservative of other LGBT topics.Also, she could have been a boy dressing as a girl at a young age.
- Waylon Smithers - Smithers hinted at possibly being transgender when Marge was selling prescription medication at a garage sale and he bought bottles of estrogen for "a friend...who's trapped in the body of another friend." He also hints at transvestite tendencies in "When You Dish Upon a Star" when he asks Kim Basinger where to get red pumps similar to those her character wears in LA Confidential, and also in "Weekend at Burnsie's" where Smithers, while stoned from smoking a joint of marijuana in order to allow Homer to keep his vow of not using marijuana after quitting it, proceeded to dress up as Judy Garland and suggested that Homer dress up as Mickey Rooney before realizing after Homer noted that the latter was of 60 Minutes fame that Mr. Burns had been gone for over an hour, far too long regarding his bath. Although not a true hint, the end credits for "Dial "N" for Nerder" had among the "cast" Smithers dressed up in drag as the "wife" of Mr. Burns.
- Dewey Largo - Sought gender reassignment surgery from Dr. Nick, but because Nick had the surgery files mixed up, Largo ended up getting an operation intended for Moe, which made him shorter.
- Frank Simpson - Homer Simpson's history about Frank Simpson implied that Frank changed his gender in 1976.
- Martin Prince - In Holidays of Future Passed, Adult Lisa gets a Facebook-like friend request from Adult Martin Prince, known as Marsha Princess before he turned back into a man.
- ↑ 1.0 1.1 1.2 1.3 There's Something About Marrying
- ↑ 2.0 2.1 The Color Yellow
- ↑ Homer Is Where the Art Isn't
- ↑ 4.0 4.1 Flaming Moe
- ↑ 5.0 5.1 Homer's Phobia
- ↑ Sleeping with the Enemy
- ↑ Three Gays of the Condo
- ↑ Lisa vs. Malibu Stacy
- ↑ Large Marge
- ↑ That '90s Show
- ↑ Catch 'Em if You Can
- ↑ Simpson and Delilah
- ↑ Homer Simpson, This Is Your Wife
- ↑ Bart's Comet
- ↑ Pygmoelian
- ↑ Homerazzi
- ↑ Homer and Lisa Exchange Cross Words
- ↑ Marge and Homer Turn a Couple Play
- ↑ I'm with Cupid
- ↑ Bart's Inner Child
- ↑ Jaws Wired Shut
- ↑ Two Dozen and One Greyhounds
- ↑ Today, I Am a Clown
- ↑ The Simpsons Movie
- ↑ I Love Lisa
- ↑ Lisa's Sax
- ↑ Future-Drama
- ↑ Homer's Night Out
- ↑ http://www.hollywoodreporter.com/live-feed/simpsons-season-29-preview-comic-con-2017-1023604
- ↑ Moms I'd Like to Forget
- ↑ Homer the Smithers
- ↑ Secrets of a Successful Marriage
- ↑ The Parent Rap
- ↑ Wedding for Disaster
- ↑ Bart's Girlfriend
- ↑ The Way We Weren't
- ↑ We're on the Road to D'oh-where
- ↑ Eeny Teeny Maya, Moe
- ↑ Lisa's First Word