LGBT characters

These are characters that are lesbian, gay, bisexual or transsexual.

Openly gay characters

 * Patty Bouvier - She almost married Veronica in "There's Something About Marrying".
 * John(Homer's Phobia)
 * Grady
 * Julio
 * Roscoe (Homer's Phobia)

In the closet

 * Waylon Smithers

Hinted to be Gay

 * Lenny Leonard - Sometimes hinted as being attracted to Carl.
 * Carl Carlson - Sometimes hinted as being attracted to Lenny.
 * Dewey Largo
 * Karl (Simpson and Delilah) - kissed Homer on the lips when he briefly returned after stating that his mom told 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.
 * Lisa SimpsonIn Papa Don't Leech, she said she would like a gay scoutmaster.

Non-Canon

 * Marge Simpson
 * Lindsey Naegle

Transsexual

 * Judge Constance Harm indicates that she was born a man.
 * Brunella Pommelhorst says she will return next semester as Mr. Pommelhorst, the new shop teacher.
 * Helen Lovejoy - At one point, the Parson tells Reverend Lovejoy that he "remember[s] when [Helen Lovejoy] was Helen Schwartzbaum. In fact, I remember when she was Harold Schwartzbaum." This is questionable due to her and Lovejoy having a daughter together as well as a flashback in The Way We Weren't clearly depicting her as a little girl.
 * Waylon Smithers - Smithers hinted at possible transgendered tendencies 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."

Hinted to be Transsexual

 * Patty Bouvier - Otto Mann once asked Patty Bouvier if she was born a chick, or if she used to be a man.

Hinted to be Bisexual

 * Duffman - In Homerazzi, Bart mentions that he is supposedly in a long-term gay relationship after seeing him dining with Booberella. However, there are several different Duffmen. Later in a relationship with Julio.
 * The Sea Captain - In I'm with Cupid, Apu delivers pornographic magazines to hold off the Sea Captain's crew from going down to situational homosexuality for about ten minutes, at least. However, in Bart's Inner Child, Captain McCallister was 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 had crushed on and mated with both She's The Fastest and Rosa Barks, both of whom were evidently female.
 * Ralph Wiggum - In The Simpsons Movie, he declares "I like men now" after seeing Bart naked on a skateboard. However, he had a crush on Lisa Simpson at one point (who also was his first crush). Plus, nothing Ralph says about himself is reliable since his understanding of everything is questionable.
 * Milhouse Van Houten: Hinted to be gay, but has a crush on Lisa Simpson and has dated other girls. In one episode, he tries to confide in Bart the reason he was crying at lunch time, but Bart gets uncomfortable and changes the subject. Dr. J. Loren Pryor hinted that Milhouse was gay in "Lisa's Sax".
 * Martin Prince - was shown to have a crush on Ralph Wiggum at one point; effeminate; accused of being gay by Nelson and proclaims "I'm not anything yet"; has male robot boyfriend in the future. On the other hand, he did have an attraction to Princess Kashmir in Bart's photo of her dancing with Homer in Homer's Night Out, even referring to it as being "quite exciting" and calling her a "sexy lady" when he asked Bart who she was.
 * Principal Seymour Skinner: was forced into Kissing Groundskeeper Willie in "Stealing First Base" and appeared to rather enjoy it. however, almost married and dated Edna Krabappel.
 * Groundskeeper Willie: enjoyed being forced to kiss Principal Seymour Skinner by Superintendant Chalmers; later kissed him of his own free will at the end of the episode. However, Groundskeeper did once remark under the influence of Peyote Juice that he had waited years for the moment that he would make out with Fergie (A female)