In-show deaths

Even though The Simpsons primarily maintains the status quo, throughout the run of the series, several characters, both recurring and one-time, have died. Additionally, many characters have been jokingly killed off during the Treehouse of Horror episodes.

Deaths During the Series

Hubert Simpson

The Simpsons shorts

• Hubert Simpson - died in "The Funeral"

Flashbacks

• Clancy Bouvier - In "Jazzy and the Pussycats", Homer says that he died. In "Puffless", it is revealed that he died of lung cancer.
• Snowball I (1984-1989) - died after being hit by a car, being driven by Clovis Quimby. The death is first mentioned in "Simpsons Roasting on an Open Fire" with Clovis Quimby being mentioned as the killer in "Treehouse of Horror III".
• Orville Simpson - seen in Heaven by Bart in "Bart Gets Hit by a Car".
• Milton Haas - died from a hernia while carrying the crate of stolen Nazi paintings out of the German castle.
• Sheldon Skinner, Arnie Gumble, Iggy Wiggum, Etch Westgrin and Griff McDonald - killed during a 1979 parade accident.
• Johnny - killed by the Vietnamese during Skinner's Valentine's Day flashback in "I Love Lisa".
• Soldier - eaten by an elephant during the Vietnam War despite Skinner's warning in "Skinner's Sense of Snow".
• C. W. McAllister - died on the Murderhorn mountain in 1928, presumably from altitude sickness as his oxygen was stolen. Abraham Simpson II has taken a bite out of his arm. His body was only found in "King of the Hill".
• Waylon Smithers, Sr. - died of radiation poisoning. When he was younger, Homer Simpson discovered his body, presumably a while after his death as it had quite substantially decayed. Homer had flashbacks of the event when he was hypnotized in "The Blunder Years". Mr. Burns later showed the Simpson family, as well as Chief Wiggum and Waylon Smithers, Jr., the footage of his death, which shows that he had died saving Springfield.
• Asa Glick - held a grenade in his hand too long during WWI and was blown up.
• Child actor - playing Alfalfa on Our Gang, beaten to death by Moe Szyslak as seen in a flashback in "Radioactive Man".
• Viktor's wife - accidentally killed by Wayne Slater by a bullet.
• Mr. Teeny I, II and III - Krusty remarks that he hasn't been this sad since Mr. Teeny III died in "Fraudcast News".
• Pa - died at some point before "How Munched Is That Birdie in the Window?".
• Sheep - stabbed by Mr. Burns and later died in an explosion in "Moe Goes from Rags to Riches".
• Persian Jimbo, Kearney and Dolph - got decapitated in "Moe Goes from Rags to Riches".
• Man About to Be Executed by Axe - stabbed in the head by an axe in "Moe Goes from Rags to Riches".
• Bumblebee Man's Parents - shot while playing paintball in "Four Regrettings and a Funeral".
• Grandma Flanders - died from hearing Ned's song of praise (according to Homer) in "The Kids Are All Fight".

Season 1

• Snowball I - was mentioned to have been ran over by a car, which most likely happened somewhere just before the events of "Simpsons Roasting on an Open Fire" and was replaced by Snowball II.
• Rabbit - possibly died of great height after Homer and Bart's trap flung him in the air in "The Call of the Simpsons".

Season 2

• Beetle - eaten by Santa's Little Helper in "Bart's Dog Gets an F"
• Beatrice Simmons - died of a burst ventricle in "Old Money", although Abraham Simpson II says that it was actually a "broken heart" after he was unable to attend her birthday party.

Season 3

• Snuffy (Lisa's pet hamster) - his death was mentioned in Lisa's poem in "Stark Raving Dad".
• Abraham Lincoln Squirrel - mentioned to have been assassinated in "Radio Bart".
• Stinky and Winckels - Killed by Bart and his yo-yo, whilst trying the pickle trick in "Bart the Lover".
• Hamster - died on an operating table in "Dog of Death".

Season 4

• Aunt Gladys Gurney - died in "Selma's Choice".
• Numerous people - apparently fell to their deaths after riding on the Escalator to Nowhere in "Marge vs. the Monorail".
• Truck Driver - most likely perished after going off the road and crashing into a hill in "Krusty Gets Kancelled".

Season 5

• Burns' Flying Monkeys - fell out the window after they failed to fly in "The Last Temptation of Homer".
• Boris Simpson - left the Simpson family his house when he died in "Homer Loves Flanders".
• Man - got his head exploded by the loud Deep Note of the THX trailer in "Burns' Heir".

Season 6

• Bleeding Gums Murphy - died in the hospital from illness in "'Round Springfield".
• Superdude (the school gerbil) - crushed by his water bottle in "Who Shot Mr. Burns? (Part One)".
• Dr. Marvin Monroe - It was originally thought that Marvin Monroe was dead. In "Who Shot Mr. Burns? (Part Two)", the hospital Burns attends is named Marvin Monroe Memorial Hospital, and since that, his gravestone has been seen. Most prominently, in "The Simpsons 138th Episode Spectacular", one of the trivia questions asked was "Which two popular characters have died in the past year?" With the answer being, "If you said Bleeding Gums Murphy and Dr. Marvin Monroe, you were wrong. They were never popular," indicating he was dead. However, Marvin Monroe re-appeared ten years later in "Diatribe of a Mad Housewife", saying that he has been "very sick", which means that Monroe never died.
• Man - fell into a sea of lava while reaching for a pay phone to answer Bart's call in "Bart vs. Australia".
• Edgar Neubauer, Prudence Goodwife, Buddy Holly, Ritchie Vallens, The Big Bopper, Humphrey Boa-Gart, Mr. and Mrs. Bananas - their tombstones are seen when Bart and Lisa visited the cemetery in "Sideshow Bob Roberts". The cause of their deaths are unknown.

Season 7

• Unknown number of people in Shelbyville - presumably died when the Springfieldians knocked Mr. Burns' sun blocker on Shelbyville in "Who Shot Mr. Burns? (Part Two)".
• Hortense Simpson - died sometime before "Bart the Fink" and left the Simpsons $100 each.
• Asa Phelps - died in "Raging Abe Simpson and His Grumbling Grandson in "The Curse of the Flying Hellfish"", leaving Abraham Simpson II and Charles Montgomery Burns as the last two surviving members of their army unit, and the last two in line to inherit the stolen Nazi paintings.
• Mr. Estes (a publications advisor) - died and left Lisa Simpson in charge of the school yearbook, sometime before "Summer of 4 Ft. 2".
• Fish - died when Homer throws a firework into the dishwasher and explodes in "Summer of 4 Ft. 2". Its skeleton can be seen after the explosion.

Season 8

Frank Grimes tombstone

• James Bont - shot to death by Hank Scorpio's guards in "You Only Move Twice".
• Convicted Man - was about to be executed in Springfield State Prison's electric chair when Hurricane Barbara lifted the roof off the prison and pulled him into the air, ostensibly to safety. He subsequently landed on some power lines and was electrocuted in "Hurricane Neddy".
• Frank Ormand - died in a car crash in "The Twisted World of Marge Simpson".
• Executor of Frank Ormand's will - died in a car crash along with Frank Ormand in "The Twisted World of Marge Simpson".
• Shary Bobbins - died after being sucked into a jet engine in "Simpsoncalifragilisticexpiala(Annoyed Grunt)cious".
• Frank Grimes - died of electrocution after touching some cables marked "Extremely High Voltage" without safety gloves, while mockingly impersonating Homer Simpson in "Homer's Enemy". He was alluded to later on in the series in "Natural Born Kissers" when Homer found a program from his funeral in a blazer pocket, as well as in "The Great Louse Detective" when Frank Grimes, Jr. tries to murder Homer to avenge his father's death.
• The Fish in Disco Stu's shoes - died presumably because of using up all of the oxygen in their water, or from constant trauma, considering they were in aquariums in Disco Stu's shoes in "The Twisted World of Marge Simpson". Stu explained that he "can't get them out of there".
• The Budweiser Frogs - eaten by The Coors' gator in "The Springfield Files".
• Man - died after waking up from a 23 year coma in "The Springfield Files".
• Geech (Merl's dog) - got accidentally sealed in concrete by his owner in "Brother from Another Series".
• Kissing Fish - eaten by the other one in "El Viaje Misterioso de Nuestro Jomer (The Mysterious Voyage of Homer)".

Season 9

• Boar - killed and eaten by Bart and the other Springfield Elementary School kids, except Lisa in "Das Bus".
• Mouse - stomped by Apu's Elephant in "The Two Mrs. Nahasapeemapetilons".
• Captain Tenille - presumably died when Homer Simpson torpedoed him out of a submarine in "Simpson Tide".

Season 10

• Pinchy (Homer Simpson's pet lobster) - accidentally got cooked to death when the bath water he was in was too hot. An extremely upset Homer ate Pinchy later at dinner in "Lisa Gets an "A"".
• Red Barclay - died after a beef-eating contest. Dr. Hibbert, a partner of the steakhouse, says he died of beef poisoning, although it was "probably from some other restaurant" in "Maximum Homerdrive".
• Mother bird - accidentally got shot by Bart with Nelson Muntz's BB gun. The gun had a crooked sight, which meant that despite the fact that Bart was aiming away from the bird, he still killed it. Bart had to look after her eggs in "Bart the Mother".
• Many birds - presumably killed by Bolivian Tree Lizards in "Bart the Mother".

Season 11

• Maude Flanders - died in "Alone Again, Natura-Diddily" when she was knocked off a racetrack grandstand by t-shirts shot from cannons. She was killed off due to problems with her voice actress Maggie Roswell. Maude's death is considered to be the most show-changing death, and affected Ned Flanders in several episodes after the incident.
• Cornelius Chapman (the only man in Springfield older than Mr. Burns (at 108 years old)) - died onstage from a heart attack after getting a kiss on the cheek from Britney Spears. Fittingly enough, he was receiving an award for Springfield's Oldest Man in "The Mansion Family".
• The Laramie Cigarettes Team - died when the helicopter exploded at the hands of a Tomacco-addicted sheep (who was the only survivor) in "E-I-E-I-D'oh".
• Duffman - died when Moe put a sticker over his face in "Pygmoelian". However, Duffman is still alive, as he is portrayed by several actors.

Season 12

• Man Having Operation - died when a tennis ball landed in his open chest after Dr. Hibbert decided to operate on him outside in "Tennis the Menace".
• Woman - starved to death when she went on a hunger strike against Duff about not cleaning the lady's room; Bart points out to her skeleton remains later in "Hungry, Hungry Homer".

Season 13

• Professor Huntington - committed suicide by walking into a lake and was dying of cancer in "Homer the Moe".
• Mr. Stimson - died of nursling rejection (his death was mistaken to of been Abe Simpson who had passed away) in "The Old Man and the Key".
• Butterfly - burnt to a crisp from a heat wave in "Poppa's Got a Brand New Badge".
• Blackout Survivor - got crushed by the Statue of Jebediah Springfield when he was happy that he is surviving the blackout. He wants to be remembered as a hero before he dies in "Poppa's Got a Brand New Badge".

Season 14

• Italian Man - got shot multiple times by Fat Tony, Legs and Louie in "The Great Louse Detective".
• Congressman Horace Wilcox - died of a stroke in "Mr. Spritz Goes to Washington".
• Andy - died when he failed Moe's drink-a-gallon-of-gin challenge in "'Scuse Me While I Miss the Sky".
• Turtle and Skunk - got crushed to death when Kirk Van Houten accidentally crushed them with a flag in "The Bart of War".

Season 15

• Lawyer - died when Homer drove over him in "My Mother the Carjacker".
• Diver - got electrocuted in "The Fat and the Furriest".
• Fishes - got electrocuted in "The Fat and the Furriest".
• Snowball II - got rammed over by Dr. Hibbert's Mercedes-Benz G500 in "I, (Annoyed Grunt)-Bot".
• Snowball III - drowned in the fish tank while trying to catch the Simpson fish in "I, (Annoyed Grunt)-Bot".
• Coltrane (aka Snowball IV) - jumped out of Lisa's window while hearing John Coltrane's music in "I, (Annoyed Grunt)-Bot" and is replaced by Snowball V.
• Nuclear Inspector - died after being rammed by Homer's car in "Diatribe of a Mad Housewife".
• Skin Mite and possibly his family - dissolved by a beauty product on Marge's skin in "The Wandering Juvie".
• Presumably everyone within the Dayton Arms Hotel - died in the twister while it obliterated the hotel onscreen (all the way to the basement) in "Catch 'Em if You Can".
• Presumably everyone in a nearby bus including Duffman - died in the twister when their bus got sucked up and launching it far away by the twister in "Catch 'Em if You Can".

  

  The people in the bus meet their fate

• Elmo - hung himself after being wrongly imprisoned at the Ronald Reagan Reeducation Center in "Bart-Mangled Banner".

Season 16

• James Caan - got shot many times by Cletus‘ gang in "All's Fair in Oven War".
• Health Inspector Frankie - died after eating one of Moe Szyslak's pickled eggs in "Mommie Beerest".
• Mario - got hit by a trash can that was thrown by Homer in "Homer and Ned's Hail Mary Pass".
• Los Lobos - died with other celebrities in a tragic blimp accident in "Thank God It's Doomsday".
• Lisa's Hamster - Lisa mentioned that Bart tried to cheer her up after her hamster's death when she was young in "On a Clear Day I Can't See My Sister".
• Bart's Turtle - died for an unknown reason and Bart asks Homer to save her during the shock therapy in "Don't Fear the Roofer".

Season 17

• Buried Man - died after being buried alive by Gravedigger Billy in "The Girl Who Slept Too Little".
• Bird Egg - eaten by Nelson but was later attacked by other birds in "The Last of the Red Hat Mamas".
• Fred Kanneke (Chief Wiggum's brother-in-law) - was given euthanasia in "Million-Dollar Abie".

Season 18

• The Callibricis (the rival gang of Fat Tony) - died of food poisoning in "The Mook, the Chef, the Wife and Her Homer".
• The Callibricis' Goons - died in a car explosion (except for Joey (mafia)) in "The Mook, the Chef, the Wife and Her Homer".
• Amber Simpson (Homer's Vegas wife) - died of an overdose whilst in front of a "Do not stand up on the roller coaster" sign. Her funeral was seen in "Jazzy and the Pussycats".
• Max (an ice cream truck driver) - died while giving Homer change for $100 in "Ice Cream of Margie (with the Light Blue Hair)".
• Diver - drowned after Nelson stole his equipment in "The Haw-Hawed Couple".
• Possibly many of the population of Shelbyville - got killed when an atomic bomb detonates there in "24 Minutes".
• Cottontail (Bart's rabbit) - died and Homer buried him in "The Boys of Bummer".

The Simpsons Movie

• Green Day - drowned when the boat they were playing on flipped over. The Springfield residents later prayed for them in church.
• Fishes in Lake Springfield - got electrocuted by Homer with a bug-zapper.
• Panicky Man - crushed by the dome as it was being installed over Springfield, killing him.
• Dr. Nick - got crushed by a piece of the dome that landed on his groin and said, "Bye-bye, everybody!". It turns out he was not killed (possibly due to the piece of the dome knocking him out unconscious) and made several appearances in later episodes.

Season 19

• People Reviewing Sundance Films - died from loss of breath in "Any Given Sundance".
• Mona Simpson - died of old age in "Mona Leaves-a".

Season 20

• Mrs. Gumble - died sometime before "Double, Double, Boy in Trouble".
• Howard, Sr. - died sometime before "Wedding for Disaster".
• Fly - got squashed by Homer's head in "The Good, the Sad and the Drugly".

Season 21

• Gypsy (in the couch gag for "Boy Meets Curl") - she gave Grampa the tarot card of Death, but Grampa turns it to her, causing her to get a heart attack.
• Every ant from Lisa's ant farm except for Annie - got eaten by Santa's Little Helper in "American History X-cellent".
• Annie - eaten by Santa's Little Helper just as she was released into the wild in "American History X-cellent".
• Bluella - died after she was washed up onto shore in "The Squirt and the Whale"
• Bird - died after Homer accidentally shot it with a crossbow when Lisa diverts the shot from sharks.

Season 22

• Raymond Bird - eaten by Santa's Little Helper in "How Munched Is That Birdie in the Window?".
• Fat Tony - died presumably from a heart attack, because he couldn't take it that Homer betrayed him in "Donnie Fatso". Fit Tony took his cousin's place running the Springfield mob.
• The Only Woman for Moe - hung herself after thinking there was no man for her in "The Blue and the Gray".
• People On Airplane - presumably died in a plane crash when Patty and Selma remove their smoke and ash from their hair and caused the plane to crash in "The Blue and the Gray".
• The Hardy Boys - their gravestones are seen in "500 Keys" when Lisa asks what Nancy Drew would do.
• Nancy Drew - her gravestone is lying in the ground next to "The Hardy Boys" in "500 Keys".

Season 23

• Viktor - choked to death from an ice pick that Wayne Slater threw into his throat in "The Falcon and the D'ohman".
• Alice Glick - killed by a rogue seal robot in "Replaceable You".
• 35 Citizens - got killed during the reign of Springface in "The D'oh-cial Network".

Season 24

• Steve Mobbs - died sometime before "A Tree Grows in Springfield".
• Frog - zapped by Chief Wiggum in "Pulpit Friction".

Season 25

• Chip Davis - died in "Four Regrettings and a Funeral".
• Lyla - died in "Four Regrettings and a Funeral".
• Edna Krabappel - implied to be deceased in "The Man Who Grew Too Much" and in the chalkboard gag reading, "We'll miss you, Mrs. K" due to Marcia Wallace's death.

Season 26

• Rabbi Hyman Krustofsky - died of natural causes in "Clown in the Dumps".
• Albert, died after attempting to stand on his own in "Walking Big & Tall".
• Squawky - killed by the engine of Elon Musk's flying vehicle in "The Musk Who Fell to Earth".
• Caveman Homer - Died after falling in a tar pit after inventing the sandwich in "Super Franchise Me".

Season 27

• The Pit Master - died of an unknown cause in "Cue Detective".
• Cupid - got shot by Cletus in "Love Is in the N2-O2-Ar-CO2-Ne-He-CH4".
• Nibbles (the class hamster) - died after being neglected by Lisa in "Lisa the Veterinarian".
• Grand Canyon visitor - possibly died after being crushed by falling boulders in "Fland Canyon".
• Grand Canyon Restaurant waitress' Brother - died after being sentenced to death by electric chair in "Fland Canyon".
• Lenny's Grandmother - possibly died during "Simprovised". It is mentioned that she was very sick, and later, Lenny mentioned that the hospital "left a message" and left the room crying.

Season 28

• Dr. Nussbaum - died after an appointment with Mr. Burns in "Friends and Family".

Season 29

• Sebastian Cobb - possibly died after being struck by the monorail in "The Old Blue Mayor She Ain't What She Used To Be". It is unknown whether he survived or not.
• Dr. Samuel Elkins- Drank rat poison so his patients would feel guilty in "Flanders' Ladder".
• Barney - Served poison by Moe (in dream) in "Flanders' Ladder".
• Barflies - Served poison by Moe (in dream) in "Flanders' Ladder".
• Many People - Killed after their train crashed in "Flanders' Ladder".

Future episodes

The contents of this article or section are considered to be non-canon and therefore may not have actually happened/existed.

• Many Mosquitoes - got hit by the Simpsons' car windshield in "Bart to the Future".
• Homer Simpson - died 50 years later in "Barting Over".
• Homer and Marge Simpson - became ghosts 60 years later in "The Boys of Bummer".
• Ralph Wiggum - accidentally shot himself in the head in "Holidays of Future Passed".
• Ralph Wiggum Clone #1 - got hit by a truck in "Holidays of Future Passed".
• Ralph Wiggum Clone #2 - crashed the truck in "Holidays of Future Passed".
• Numerous Ralph clones - got set on fire as a result of the truck crash in "Holidays of Future Passed"
• Bart Simpson - pulled apart by snowmobiles, as revealed 1000 years later in "The Father, the Son and the Holy Guest Star".
• Sanjay Nahasapeemapetilon, Capital City Goofball, Sideshow Bob, Gary Chalmers and Edna Krabappel - revealed to have died sometime before 30 years later in "Holidays of Future Passed".
• 127 Homers - died for various reasons in "Days of Future Future".
• Scruffy - shot himself in the head with a laser gun in "Simpsorama", because he realized life was not worth living without a moustache. However, during the end credits, his body is shown moving while sweeping the ground without a head.
• Abraham Simpson II - died sometime in "Barthood".
• Waylon Smithers, Jr. - jumped in a tank of nuclear material after seeing that Mr. Burns is in love with another woman in "Flanders' Ladder" .
• Homer Simpson - shot by Clancy Wiggum after leaving the food bank with a sandwich in "Flanders' Ladder".
• Clancy Wiggum - choked to death on Homer's sandwich in "Flanders' Ladder".
• Seymour Skinner - died of a heart attack when Bart launched fireworks into the air saying "Skinner Sucks" in "Flanders' Ladder".
• Bart Simpson - run over by Skinner's corpse in a wheelchair in "Flanders' Ladder".
• Lisa Simpson - died while meditating in "Flanders' Ladder", realizing it was all a waste of time.
• Marge Simpson - died while sipping tea, remarried to Flanders in "Flanders' Ladder".
• Ralph Wiggum - died after his son poisoned his drink, and his son becomes the new king in "Flanders' Ladder".

Fictional characters

Itchy and Scratchy usually get killed (mostly Scratchy) in their episodes.

Season 2

• Cartoon Squirrel, gets her head swung off by Itchy's bat in "Itchy & Scratchy & Marge".

Season 8

• Poochie, died on the way back to his home planet during an episode of the Itchy & Scratchy Show in "The Itchy & Scratchy & Poochie Show". He was killed off due to immense unpopularity. However, he still appears as a background character from time to time, so he may not actually be dead. For example, he appeared in non-canon segment "The Terror of Tiny Toon" in "Treehouse of Horror IX".

Season 14

• Eric Cartman, head cut off by O.J. Simpson in a South Park episode that Bart and Milhouse were watching in "The Bart of War".
• Farty the Crippled Robot, head cut off By O.J. Simpson in a South Park episode that Bart and Milhouse were watching in "The Bart of War".

Season 15

• Mr. O'Bannon, a character in the video game Hockey Dad, killed in the fight in "The Regina Monologues".
• Cyrus Manley, character in Marge Simpson's book, the Harpooned Heart, murdered by Captain Mordecai Barrows with a harpoon.
• Captain Mordecai drowned.

Season 18

• Greystach, a character in the Angelica Button series, is killed by Malicious Krubb after he tries to save Angelica Button.
• Officer Joe, a character in "Dunderhead Deputies in Farmyard Follies", kills himself after he saw the "WANTED OFFICER JOE" poster and got sent to hell in "The Wife Aquatic".

Season 24

• Silly Squirrel, gets murdered by an acquaintance in "The Saga of Carl". 

  

  Comic Book of the death of radioactive man

Season 25

• Radioactive Man, died in "Married to the Blob".

Treehouse of Horror deaths

Note: Treehouse of Horror deaths are kept separate due to the nature of Treehouse of Horror episodes. Treehouse of Horror episodes aren't continuous with the rest of the series, giving the writers the possibility of killing off important characters without having to create a replacement or write them out of the series. (e.g. in Treehouse of Horror XV, Homer obliterates Springfield, but the series continues on)

The contents of this article or section are considered to be non-canon and therefore may not have actually happened/existed.

Treehouse of Horror

• Marge Simpson (as Lenore), referred to as "Lost Lenore" in "The Raven" segment of an unknown cause.

Treehouse of Horror III

• Lenny Leonard, eaten by King Homer.
• Waylon Smithers, eaten by King Homer.
• Shirley Temple, eaten by King Homer.
• Dave Shutton, crushed by King Homer.
• Clancy Bouvier, eaten by King Homer.
• Principal Skinner, turned into a zombie.
• Martin Prince (possibly), turned into a zombie when Principal Skinner as a zombie told him to bring his big juicy chess-club brain along with him.
• Krusty the Clown, turned into a zombie when a zombified Sideshow Mel bit him.
• Jimbo, Dolph and Kearney, turned into zombies (they still bullied Zombie Skinner by kicking his head).
• Nelson Muntz (possibly), may have turned into a zombie.
• Numerous zombies (Ned Flanders, Albert Einstein, Thomas Pynchon, William Shakespeare, Edna Krabappel and George Washington), killed mainly by Homer when zombies attack Springfield.

Treehouse of Horror IV

• Groundskeeper Willie's mule, Willie comments that he had to put seventeen bullets in him.
• Hans Moleman, killed when his car explodes. 
• Ned Flanders, killed by a gremlin through decapitation. (although he was still able to speak)
• Bart Simpson, bitten by Mr. Burns who was a vampire, turned into a vampire.
• Charles Montgomery Burns (Count Burns), died of a stake through heart by Homer after first staking his crotch.
• Milhouse Van Houten, Janey, Ralph Wiggum and Martin Prince, turned into vampires.
• Homer Simpson, Marge Simpson, Maggie Simpson, Grampa Simpson, turned into vampires (Note: This was off-screen.)
• Lisa Simpson, possibly turned into a vampire before the end credits rolled.

Treehouse of Horror V

• Moe Szyslak, hung.
• Patty and Selma Bouvier, burned at the stake by Reverend Lovejoy.
• Edna Krabappel, Homer Simpson, Charles Montgomery Burns, Groundskeeper Willie, Clancy Wiggum and Seymour Skinner, heads chopped off by Bart.
• Groundskeeper Willie, stabbed in the back with an axe in each of the three segments, all while trying to help the main character of the episode. In the third death, he replies that he's "bad at this."
• Patty Bouvier, revealed to have died in an alternate universe. The cause of her death, however, is not mentioned.

  

  Willie stabbed by an insane Homer in "The Shinning".

• Selma Bouvier, revealed to have died in an alternate universe. The cause of her death, however, is not mentioned.
• Mosquito, squashed by Homer.
• Walking fish, sat on by Homer.
• T-Rex and other dinosaurs, dies from a spreading cold when Homer sneezed at the T-Rex.
• A big dragonfly, beaten to death by Homer.
• Lizard, stepped on by Homer.
• Jimbo Jones, cooked by Skinner and turned into Sloppy Jimbos.
• Üter, cooked by Skinner and turned into Üterbraten.
• Wendell Borton, possibly killed since Lunchlady Doris had blood on her.
• Milhouse Van Houten, Bart and Lisa Simpson, fell in a giant blender. Bart woke up just as he and Lisa were about to die.

Note that the people killed in the third segment didn't die because it was in Bart's nightmare. However, Bart may have been eaten by Santa's Little Helper after being turned inside out by the fog.

Treehouse of Horror VI

• Martin Prince, strangled to death by Willie in his "Wizard of Latin" dream. Others including Sherri and Terri, Nelson Muntz, Ralph Wiggum, Jimbo Jones, Kearney Zzyzwicz, and Dolph Starbeam were all killed by Willie in several ways.
• Many people, crushed by a beer bottle mascot.
• 2 people, eaten by a peanut mascot.
• Maude Flanders, Rod Flanders, and Todd Flanders, possibly killed by Lard Lad when he crushed the Flander's house.
• Santa's Little Helper (possibly), when kicked by the Lard Lad mascot.
• Otto Mann and a school bus of kids, unknown if they got killed by a billboard of the Devil come to life. But Otto appeared at the end of the episode.
• Mascots including Lard Lad, were all killed since nobody looked at them during the musical sequence.
• Seymour Skinner, Nelson Muntz, Kearney Zzyzwicz, Dolph Starbeam, J. Loren Pryor, Jimbo Jones, Doris Freedman, Gary Chalmers and Groundskeeper Willie, possibly crushed when the devil destroyed the school through Bart's orders.
• Captain of the High School Basketball team, shot by Clancy Wiggum who thought he was a monster.
• Homer Simpson, possibly killed when he collapsed into pieces in the third dimension (although still alive when he stumbles to the real human world).
• Groundskeeper Willie, burnt in fire and turned into a black skeleton (although he could still move and talk).

Treehouse of Horror VII

• The Simpsons, killed after seeing the Grim Reaper near their couch.
• Bill Clinton and Bob Dole, ejected into space, completely naked and died off-screen because there is no oxygen in space.

Treehouse of Horror VIII

• FOX Censor, stabbed to death by the "TV parental guidance screen bug".
• Edna Krabappel, Elizabeth Hoover, Herman Hermann, Comic Book Guy, Kirk Van Houten, Brandine Spuckler, Luann Van Houten, Milhouse Van Houten, Rod Flanders, Todd Flanders, Helen Lovejoy, Bumblebee Man, Timothy Lovejoy, Jr., Krusty the Clown, Charlie, Gary Chalmers, Lindsey Naegle, Jeremy Freedman, Joe Quimby, Kent Brockman, Luann Van Houten, Agnes Skinner, Jessica Lovejoy, Nelson Muntz, Sherri, Terri, Grampa Simpson (possibly) Clancy Wiggum's hippo, and Old Jewish Man, killed by the bomb turning them into skeletons.
• Many Springfieldians, killed when the neutron bomb hits Springfield. Homer and the rest of the Simpsons family are the only survivors, while several others are turned into mutants (including Charles Montgomery Burns, Barney Gumble, Apu Nahasapeemapetilon, Carl Carlson, Lenny Leonard, Moe Szyslak, Sideshow Mel, Waylon Smithers, Jr., Clancy Wiggum, Ned Flanders, Cletus Spuckler, Otto Mann, Seymour Skinner, Lionel Hutz, Groundskeeper Willie, Captain Horatio McCallister and Dr. Hibbert) but then shot by Marge Simpson, Bart Simpson, and Lisa Simpson.
• Johnny Winter and Edgar Winter, run over by Homer, who mistook them for mutants.
• Luann Van Houten, Agnes Skinner and Elizabeth Hoover, all were burnt at the stake because they were accused of being witches. NOTE: Bernice Hibbert was possibly accused as a witch since Ned Flanders mentioned they killed many witches but Bernice Hibbert was not seen in the episode so she's most likely to be dead.
• Lisa Simpson, possibly killed by the angry mob after Homer accused her into being a witch.

Treehouse of Horror IX

• Homer Simpson, hit by Marge Simpson's car.
• Lisa Simpson, crashed into the garage door on her bike.
• Bart Simpson, accident on his skateboard.
• Marge Simpson(possibly) and Maggie Simpson(possibly), killed after crashing their car into a wall where Homer was killed.
• Snake Jailbird, electrocuted in an electric chair.
• Apu Nahasapeemapetilon, drowned in a Squishee machine by Homer Simpson.
• Moe Szyslak, Homer Simpson pulled his heart out with a corkscrew.
• Poochie, hit by a police car driven by Itchy and Scratchy.
• The Jerry Springer Show Audience, incinerated by Kang's death ray.
• Jerry Springer, suffocated by Kang's tentacle, he was also possibly killed from a venomous bite of the alien/human hybrid Maggie Simpson.

Treehouse of Horror X

• Lisa Simpson, disintegrated by the alien Maggie from Treehouse of Horror IX.
• Ned Flanders, hit by a car. However, he reappeared as a zombie werewolf, so now he is undead.
• Homer Simpson, mauled by werewolf Ned Flanders (off-screen)
• Comic Book Guy as The Collector, killed by Lucite when he fell to the plastic water.
• Nelson Muntz, falls into copying machine.
• Krusty the Clown, killed by a pace maker inside his stomach. (although he shouted "I'm not dead" which means he's alive, also Bart was upset about this)
• Homer Simpson and Bart Simpson, blown up after escaping the spaceship going into the sun, died because of no oxygen in space.
• Celebrities on doomed spaceship, died when their spaceship flew into the sun.

Treehouse of Horror XI

• Homer Simpson, killed by an angry mob.
• Bart Simpson, killed by an angry mob.
• Marge Simpson, killed by an angry mob.
• Abraham Simpson II, killed by an angry mob.
• Homer Simpson, choked to death on a piece of broccoli, twice.
• Agnes Skinner, dropped to her death by Ghost Homer when he tries to do a good deed.
• Simpson children, Bart and Lisa see their siblings’ skeletons.
• Goldilocks, mauled by Father Bear, Mother Bear and Baby Bear.
• Rapunzel, implied to be dead after her own scalp is ripped by Homer.
• Suzanne the Witch, burnt to death
• Lenny Leonard, killed by dolphins (although was seen in the battle)
• Captain Horatio McCallister, killed by dolphins.
• Squeaky-Voiced Teen, killed by dolphins.
• Kent Brockman, killed by dolphins.
• Many people including: (Apu Nahasapeemapetilon, Akira, Comic Book Guy, Carl Carlson, Reverend Lovejoy, Hans Moleman, Gil Gunderson, Raphael, Fat Tony, Louie, Legs, Luigi, Luann Van Houten, Lunchlady Doris, Montgomery Burns,Waylon Smithers, Disco Stu, Cookie Kwan, Judge Constance Harm, Lionel Hutz, Sideshow Bob and Arnie Pye) all died in the battle.
• Abraham Simpson II, eaten by a dolphin, though a deleted scene shows him bursting out of the dolphin and joining in Springfield's battle against the dolphins.
• Groundskeeper Willie, killed by dolphins.
• Krusty the Clown, drowned in the sea off-screen.
• Homer, Marge, Bart, Lisa, Maggie (possibly), Old Jewish Man, Dr. Hibbert, Charlie (SNPP), Bernice Hibbert, Moe, Barney, Ned Flanders, Sideshow Mel, Millhouse, Kirk Van Houten, Chief Wiggum, Lou, Eddie, Ruth Powers, Seymour Skinner, Agnes Skinner, Mayor Quimby, Dr. Nick, Nelson Muntz, Jimbo Jones, Kearney Zzyzwicz, Dolph Starbeam, Jasper Beardly, Snake Jailbird, Dave Shutton, Sam, Larry, Manjula, the Octuplets, Ralph Wiggum, Lindsey Neagle, Edna Krabappel, Professor Frink, Superintendent Chalmers, Helen Lovejoy, Miss Springfield, Bumblebee Man, Sherri and Terri, Üter Zörker, Duffman, The Rich Texan, Charlie, Drederick Tatum, Artie Ziff and many others, survived, drowned and left stranded in the sea. (debate, because some characters are absent in this story)
• Note: Rainier Wolfcastle is one of the few Springfield locals that does not appear in "The Night of the Dolphin".

Treehouse of Horror XII

• Waylon Smithers, electrocuted.
• Simpson family, shredded by Mr. Burns' gate after running through it.
• Lenny Leonard, crushed and killed by a helicopter that crashed on Moe's.
• Carl Carlson, crushed and killed by a helicopter that crashed in Moe's.
• Moe Szyslak, drowned off-screen in a pickled egg jar.
• Bart Simpson, drowned himself in his cereal off-screen.
• Lord Montymort, stabbed in enchanted shin (the source of his power) by Bart Simpson and Slithers eats him.

Treehouse of Horror XIII

• Homer Clone, electrocuted.
• Ned Flanders, decapitated with a chainsaw by Homer clone.
• 3 Homer clones that knew the way home, shot by Homer.
• Gil Gunderson, eaten alive by Homer clones
• All Homer clones but one, fall off a cliff.
• Real Homer Simpson, falls off a cliff.
• Zombies, shot.
• Future Homer Simpson, shot by Moe.
• Little Eyes, Eaten by Sinister Eyes.
• Professor Frink, eaten after being turned into a turkey.
• Bird, eaten by Marge.

Treehouse of Horror XIV

• Homer Simpson, shot by Marge.
• Grim Reaper, murdered by Homer with a bowling ball.
• Homeless Guy, received the touch of death by Homer the Grim Reaper so students could watch him harvest a soul (it was not seen on-screen, however).
• Jasper, received the touch of death by Homer.
• Crowd at the baseball game (Including Lindsey Naegle, Kirk Van Houten, Reverend Lovejoy and Hans Moleman), all received the touch of death by Homer (except the Queen who got hit by a baseball).
• Patty Bouvier, killed by Homer instead of Marge.
• Ned Flanders, killed by Jonathan Frink, Sr. after he rips out his heart.
• Seymour Skinner, killed by Jonathan Frink, Sr. after he rips out his spine. Note that he was still moving and talking but he was not seen later sneaking to get revenge, so he probably died.
• 5 scientists, brains removed by Jonathan Frink Sr.
• Sideshow Mel, Very Tall Man, Bumblebee Man, Superintendant Chalmers, Eddie, Snake Jailbird, Reverend Lovejoy, Otto Mann, Cletus Spuckler, Clancy Wiggum and Apu Nahasapeemapetilon, killed by Jonathan Frink, Sr. by ripping their body parts. Other characters (including Disco Stu, Nelson Muntz, Kearney Zzyzwicz and Charles Montgomery Burns) survived.
• Jonathan Frink, Sr., died form a calculated kick to the groin from Jonathan Frink.
• Martin Prince, died or was seriously injured while being attacked by the angry mob.

Treehouse of Horror XV

• Simpson family (except for Bart), cooked by Kang and Kodos.
• Dr. Hibbert, falls out of a window.
• Hans Moleman, dropped down a sewer and devoured by crocodiles.
• Homer Simpson, shot by Ned thrice. The rest of the Springfield including (Ned Flanders, Marge Simpson, Lisa Simpson, Bart Simpson, Maggie Simpson, Chief Wiggum, Carl Carlson, Montgomery Burns and Barney Gumble) were all killed by a bomb.
• Prostitute, killed by Clancy Wiggum.
• Ned, Todd and Rod Flanders, their heads hang in Comic Book Guy's shop.
• Comic Book Guy, killed by Clancy Wiggum.
• Selma Bouvier, killed by Clancy Wiggum. Note she was still talking and moving when Bart said if she died 5 minutes ago, but then she went back to dead.
• Clancy Wiggum, possibly died on a balloon crash after getting hit by Kang and Kodos' spaceship.

Treehouse of Horror XVI

• David, sliced in half by Bart.
• Lenny, Carl, Barney, Bumblebee Man, Reverend Lovejoy, Sideshow Mel, Mr. Largo, Dr. Nick, Dr. Hibbert, Principal Skinner, Groundskeeper Willie, Apu, Otto, Lou, Squeaky-Voice Teen, Kirk Van Houten, Kent Brockman, Comic Book Guy, Blue-Haired Lawyer, Krusty the Clown, The Yes Guy and Captain McCallister, all shot by Mr. Burns (Note: Apu was killed twice when he got reincarnated as a rabbit, but got trapped in a bear trap).
• Moe and Chief Wiggum, impaled on a weather vane.
• Professor Frink, eaten by Homer.
• Mr. Burns and Smithers, hit on the head with a frying pan by Marge. (Burns and Smithers may not be dead, they might be unconscious)
• Disco Stu, arrow through the head. (a la Steve Martin)
• Mayor Quimby, eaten by dogs.
• Martin Prince, sprayed by Groundskeeper Willie.
• Mouse, eaten by Bart who show his special power to everybody.
• Abraham Simpson II, It is unclear as to whether he is killed or not, but it is likely he would be listed as dead after Dr. Hibbert (who had became a vampire) flew off into the night with him. Abe said, "That's it, suck out the poison...Wait a minute...Ahhhhh!", implying that he had either been turned into a vampire (which would technically make him undead) or had been killed due to blood loss.

Treehouse of Horror XVII

• Moe Szyslak, killed by an iron maiden.
• Snowball V, eaten by Homer Simpson.
• Squeaky-Voiced Teen, eaten by Homer.
• Üter, eaten by Homer.
• German People at Oktoberfest, eaten by Homer.
• Fat Tony, eaten by Homer.
• Comic Book Guy, eaten by Homer.
• Peoples in Umpire School, eaten by Homer.
• Peoples from "The Facts of Life Reunion Tour", eaten by Homer.
• Guys in Hawaiian shirt store, eaten by Homer.
• Peoples on a bus, eaten by Homer.
• Ned Flanders, had his head bitten off by Homer.
• Dr. Phil McGraw, eaten by Homer.
• Homeless People, eaten by Homer.
• 17th Century People, shot by the Golem of Prague in a flashback.
• Bart's turtle, gets killed by Homer when he's passed out. (only mentioned, not actually seen)
• Jimbo, Nelson, Dolph and Kearney, died after the Golem switches their heads. Note: Nelson was not seen on-screen or seen when heads were switched because the Golem threw his head off.
• Principal Skinner, sliced in half by the Golem of Prague. (however, he responded with "I may be bifurcated, but I still have feelings" before being put in a bag, but he is listed by Chief Wiggum as dead, so he is probably killed by the Golem)
• Barney Gumble, hit with a bat by Moe.
• Lenny Leonard, shot by Homer, who thought he was an alien.
• Disco Stu, shot by Homer, who thought he was an alien.
• Captain McCallister, decapitated by Homer.
• Clancy Wiggum, sucked dry by Kang and Kodos' spaceship.
• Many Springfieldans, all killed in Kang and Kodos' invasion.

Treehouse of Horror XVIII

• American Idol logo, sucked away in a hoover by Marge.
• Football on Fox logo and Football players, sprayed by Marge.
• Cops Police man, melted by Marge.
• 24 Guy, stuck on the fridge by Marge. (but still alive)
• Gregory House, put in a microwave by Marge and exploded.
• Prison Break Prisoners, scared away by Marge. (but still alive)
• Three soldiers, killed by Kodos.
• Various Rigellian IV Aliens, killed by USA troops.
• Kang, shot.
• Kodos, suffocated.
• Kent Brockman, killed by Marge.
• Five men, Disco Stu and Captain McCallister, accidentally shot by Homer.
• Grampa, accidentally killed by Homer and Marge when they were trying to kill each other.
• Chief Wiggum, shot in the chest with an arrow by Marge.
• Principal Skinner, killed by Marge and Homer (although was still talking)
• Track Driver and many people in Hotel, died when Hotel destory.
• Barney Gumble, was set on fire by Bart, Milhouse, Nelson, and Lisa, or Jimbo, Kearney, and Dolph, since they were in Hell.
• Principal Skinner, killed by a school bus drive by Todd and Rod.
• Groundskeeper Willie, killed by his killer tractor.
• Dr. Hibbert, run down by a van.
• Homer, killed when he is cut to pieces through his own hammock and his head turned to spaghetti.
• Moe Szyslak, kicked by a woman.

Treehouse of Horror XIX

• Homer, killed by the voting booth when he gets sucked into it and shot out afterwards.
• Grandpa Simpson, possibly died after passing out in the Simpsons front yard.
• People On Plane (including Superintendant Chalmers), coughed out by Plane Robot onto runway.
• Various People Throughout Springfield, probably killed during robot battle. (This includes Otto since he was in the segment, but was not seen later on at the end with the others, but it is uncertain if he died)
• Krusty the Clown, shredded by a woodchipper.
• George Clooney, The Rich Texan, Prince, Neil Armstrong, Kate Winslet and other celebrities (debate from some past celebrities like George and Abraham), all killed by Homer (George Clooney drowned in quicksand, Prince was strangled with his guitar by Homer and stabbed, Neil was hit and became unconscious from a flying golf club and Kate may be drowned in chocolate).
• Edna, Artie Ziff, Carl, Lenny, Barney, Moe, Lou, Eddie and Sideshow Bob, killed by deceased celebrities that came down from Heaven.
• Chief Wiggum (possibly), shot by the deceased Edward G. Robinson.
• Homer, head blasted off by the deceased Krusty the Clown.
• Principal Skinner, possibly killed after his head cut off revealing his brain by Grand Pumpkin. (but Skinner said "Part of my brain?")
• Nelson Muntz, eaten by Grand Pumpkin, then possibly eaten by Tom The Turkey
• Kang (possibly), killed by Grand Pumpkin.
• Kodos (possibly), killed by Grand Pumpkin.
• Jeff Boomhauer and Dale Gribble, killed by Tom The Turkey.
• Grand Pumpkin, killed by Tom The Turkey.
• Many Students at the Party (including Richard, Nina Skalka, Francine Rhenquist, Lewis Clark, Ralph Wiggum, Jimbo Jones, Nelson Muntz, Kearney Zzyzwicz, Dolph Starbeam, Shauna, Jessica Lovejoy, Sherri and Terri, Bart Simpson, Lisa Simpson (fled possibly), Milhouse (fled possibly) and Nikki), eaten by Tom The Turkey at the party.

Treehouse of Horror XX

• Homer Simpson, head gets chopped off and it falls in the punch bowl at the party.
• Miss Hoover, beheaded off-screen by Bart.
• Principal Skinner, beheaded off-screen by Bart.
• Alfred Hitchcock, fell onto Death.
• Bart Simpson, accidentally killed by Lisa with a knife in his head.
• Helen Lovejoy (as a muncher), shot by Marge with a gunshot.
• Sideshow Bob, Gina Vendetti, Snake Jailbird, Grampa Simpson, Lenny Leonard, Carl Carlson, Barney Gumble, Nelson Muntz, Dolph Starbeam, Kearney, Ralph Wiggum, Arnie Pye, Agnes Skinner, Superintendent Chalmers, Sara (Springfield Elementary Student), Francine Rhenquist, Luann Van Houten, Cookie Kwan, Lugash, Rod Flanders, Todd Flanders, Hubert Wong, Martin Prince Sr. and many others, all bitten by munchers then turned into a muncher.
• Jessica Lovejoy (possibly), killed by munchers, then turned into a muncher.
• Apu Nahasapeemapetilon, killed by munchers.
• Rainier Wolfcastle, killed by munchers.
• Moe Szyslak, presumably killed when he was taken by munchers Lenny, Carl and Barney.
• Hans Moleman, Ned Flanders, Bumblebee Man, Otto Mann, Sam, Larry, Comic Book Guy, Lurleen Lumpkin, Arnie Pye, Louie and Charlie, all ran over by car.
• Squeaky-Voiced Teen, killed by muncher Kent Brockman.
• Dr. Hibbert, killed by munchers.
• Mr. Burns, killed by Homer.
• Waylon Smithers, killed by Homer.
• Homer Simpson, turned into a muncher by Muncher Mr. Burns (although Homer can still talk to Marge, Lisa and Bart)
• Doctor munchers, killed by Dr. Hibbert.

Treehouse of Horror XXI

• Bart, beaten to death by Homer with a tombstone.
• Professor Frink, killed by aging himself with a DVR remote.
• Alien inside Frink‘s stomach, might have also died when Frink into dust.
• Chief Wiggum, squashed by a giant knight piece in Chess.
• Julius Hibbert, Moe Szyslak, Otto Mann, Edna Krabappel, Apu, Seymour Skinner, Ned Flanders, Luigi, Jimbo, Nelson, Kearney, Dolph, Krusty the Clown and Bumblebee Man, possibly crushed by Slinkies.
• Rod and Todd Flanders, squashed in a tumbling block game.
• Cards, shot by Bart.
• Milhouse, suicide by drowning and (again after being resurrected) neck broken after losing a game of hangman and being hanged by the neck.
• Bart, neck broken after losing a game of hangman and being hanged by the neck.
• Seagull, poisoned.
• Pelican, stabbed with a marlin thrown by Homer at the end.
• Shark, Squid and other sea life, killed by fuel from the Rent-A-Dream.
• Roger, harpooned by Homer.
• Albatross crew, various weapons including an anchor, flare gun, blunt weapon by Homer covering up murder of Roger.
• Marge, poisoned herself with a poisoned pie because of the guilt of Homer killing the Albatross crew.
• Ned Flanders, cooked for dinner.
• Big Bird - killed by Count von Count.
• Count Dracula and Edmund (possibly) - Homer's blood which was filled with cholesterol.
• Homer - when a bat, could not fly (possibly) due to his weight and fell to his potential death, and Milhouse(as a white poodle) takes him away.

Treehouse of Horror XXII

• Charles Montgomery Burns, Snake Jailbird, Patty and Selma, Sideshow Bob, killed by Ned Flanders under Homer's order.
• Homer, choked by God.
• Two Squirrels, heads are bitten.
• Superintendent Chalmers, Eddie, Lou, Apu, Seymour Skinner, Lenny Leonard, Carl Carlson, Moe Syzslak, Barney Gumble, Otto Mann, Comic Book Guy, Cletus, Brandine, Jimbo Jones (Could have survived although he was not seen in the end.), Kearney Zyzzwicz(Same), Dolph Starbeam (Same), Nelson Muntz, Lisa Simpson, Ralph Wiggum and Snake Jailbird killed by the inhabitants on Rigel 7.

Treehouse of Horror XXIII

• Aztec Moe Syzlak, burlap sack wrapped around head and is decapitated by a guard.
• Homer Simpson, crushed by a Mayan God.
• Everyone, crushed by the Mayan gods when they destroyed people's buildings as well as blowing up the entire planet.
• Sideshow Mel, had his skeleton sucked away by the black hole.
• Chief Wiggum, eaten by the devil and turned into a skeleton.
• Scratchy, had his chest impaled on a faucet and had his blood poured out of it.

Treehouse of Horror XXIV

• Kaiju Three Eyed Crow, Struck by lightning.
• Lard Lad Mascot, Eaten by a Chief Wiggum Cyclops.
• Edna Krabappel, Attacked and possibly devoured by Alfred Hitchcock's birds (debatable).
• Jimbo Jones,  Nelson Muntz, Kearney Zzyzwicz and Comic Book Guy, Turned into munchers.
• Lenny Leonard and Ralph Wiggum, decapitated.
• Fairy Waylon Smithers, Eaten by Monster Mr. Burns.
• Milhouse, Eaten by Kaiju Blinky after being pushed over the bridge by Maggie on her haunted car.
• Montgomery Burns, Superintendent Chalmers, Agnes Skinner, Ms. Hoover, Moe Szyslak, Principal Skinner, Barney Gumble, Reverend Lovejoy, Helen Lovejoy, Kirk Van Houten, Luann Van Houten, Cookie Kwan, Squeeky Teen, Bumblee Man, Duffman, Disco Stu, Krusty, Sideshow Mel, Apu, Cletus, Groundskeeper Willie, Nick Riviera and Julius Hibbert, possibly killed by monsters.
• Homer Simpson, Squashed by the car Maggie was driving.
• Some fairies, flew into the TV, got electrocuted and fell.
• Mr. Burns, turned into Roast vulture by the Fat in the Hat.
• Waylon Smithers, burned.
• Moe Syzslak, skinned by the Fat in the Hat.
• Patty and Selma, killed by the Fat in the Hat.
• Ralph Wiggum, speared to death.
• Krusty Bull, beheaded by Sideshow Bob.
• Homer Simpson (The Fat in the Hat), stabbed by Maggie and converted in a carpet.
• Jimbo Jones, Kearney Zzyzwicz and Dolph Starbeam, eaten by circus lion.
• Kang and Kodos, suffocated by Mr. Burnsrum.
• Mr. Burnsrum, hanged to death off-screen by freaks Moe Syzslak, Barney Gumble, Lenny Leonard, Carl Carlson, Nelson Muntz, Comic Book Guy, Cletus and Brandine, Raphael, Mr. Teeny and Maya.
• Homer Simpson, Babe Ruth and Stalin, all died (shown on the newspaper)

Treehouse of Horror XXV

• Homer Simpson, eaten the small intestine himself.
• Bart Simpson, decapitated by Lisa Simpson.
• Jennifer Lawrence, Warren Beatty, Clint Eastwood, George Clooney, Prince, Taylor Swift, Sean Penn, Bruce Springsteen, Helen Mirren, Morgan Freeman, James Franco, Kanye West and Leonardo DiCaprio, killed by Kang and Kodos and made them into body parts for the Treehouse of Horror XXV title.
• John Travolta, blasted on the head by Kang and Kodos.
• Hans Moleman (as a demon), axed in half by Beelze-Bart.
• Jimbo Jones, decapitated by Beelze-Bart.
• Homer Simpson, body sliced and beheaded by Beelze-Bart, however, he is still alive at the time.
• Sideshow Mel, beaten to death by Homer.
• Moe Szyslak (possibly), beaten to death.
• Marge Simpson, killed herself while washing the oven.
• Homer Simpson, killed by the Tracey Ullman Show Homer ghost by hitting him on the head with a toaster.
• Lisa Simpson, jumped out of the window and fell to her death and she turned into a ghost.
• Bart Simpson, suffocated by Lisa (as a ghost) with Bart's slingshot and he turns into a ghost.
• Maggie Simpson (possibly), killed by Groundskeeper Willie, although he was carrying Maggie's carcass along with Bart's and Lisa's dead bodies and she turns into a ghost.
• Gerald, killed by Maggie (as a ghost) and he turns into a ghost.
• Marvin Monroe, unknown.
• Snowball V (possibly), it is unknown if she was killed by the ghosts.
• Santa's Little Helper (possibly), it is unknown if he was killed by the ghosts.

Treehouse of Horror XXVI

• Nelson Muntz, Milhouse, Ralph Wiggum and Jessica Lovejoy, all hanged to death.
• Homer Simpson, his soul got eaten by a ghost monster Frank Grimes.
• Bart Simpson, killed multiple times by Sideshow Bob.
• Louie, was presumably killed since how Fit-Fat Tony mentioned him on Facebook.
• Leprecchaun, killed by Sideshow Bob to make a device that could revive
• Sideshow Bob, beheaded by Homer Simpson, but was later revived as a disconfigured chicken and his head remained.
• Professor Frink, squashed to death by Homerzilla.
• Moe Szyslak, roasted and burned to death by Homerzilla.
• Kearney, killed by Milhouse after dumping him into the volcano.

Treehouse of Horror XXVII

• Sideshow Bob, Leprechaun, Kang and Frank Grimes' ghost, all decapitated by Maggie.
• Couch, knocked out by Homer with a stone.
• Tortoises, killed by Apu so he can sell their water.
• Ralph Wiggum, exploded before the Hunger Games-esque contest started.
• Peta and Pita, killed by Homish.
• Gerald Samson, killed by a shotgun's recoil.
• Wendell Borton, killed by Nelson.
• Ned Flanders, probably killed by Barney, as his head is in the front of the Plow King.
• Nelson Muntz, shot in the back by Milhouse.
• Mr. Burns, probably killed by either the Springfieldians or the flood.
• Springfield residents, probably died during the snow storm.
• Janey Powell, killed with a lawnmower by Rachel.
• Sherri and Terri Mackleberry, killed by Rachel via a falling tombstone during Janey's funeral.
• Ms. Mancuso-Gluckman, killed by Rachel with a "It gets better" painting.
• Deer and Buddha, ran over by Lisa on her dark imagination.
• Milhouse Van Houten, asphyxiated to death with a plastic bag by Rachel.
• Snowball V, accidentally killed by Rachel as he jumped in front of a knife thrown at Marge.
• Sergeant Sausage, microwaved by Rachel and later eaten by Homer.
• Rachel, killed by Lisa, when Lisa imagines Rachel as her mom married to a dentist, and fading in the process.
• Dolph, Jimbo and Kearney, killed by Moe.
• Carl Carlson (possibly), electrocuted.
• Marvin Monroe and Üter Zörker
• Dewey Largo, Gary Chalmers, Selma Bouvier, Patty Bouvier, Disco Stu, Nelson Muntz, Mrs. Muntz, Melvin Van Horne Rainer Wolfcastle, Agnes Skinner, Seymour Skinner, Apu Nahasapeemapetilon, Manjula Nahasapeemapetilon, Cletus Spuckler, Brandine Spuckler, Luann Van Houten, Blue-Haired Lawyer, Helen Lovejoy, Julius Hibbert, Bernice Hibbert, Dr. Hibbert's Second Daughter, Roy Snyder, Legs, Frankie the Squealer, Eleanor Abernathy, Lindsey Naegle, Horatio McCallister, Comic Book Guy, Drederick Tatum, Jasper Beardly, Roger Meyers, Jr., Charlie (SNPP), Elizabeth Hoover and other members of the mob, killed by Moe, Bart, Groundskeeper Willie, Gil Gunderson and Barney Gumble.
• Moe, Groundskeeper Willie, Gil Gunderson and Barney Gumble, killed by the angry mob.
• Homer Simpson, killed by Bart.

Treehouse of Horror XXVIII

• Nelson Muntz (as Nelson's Crunch) and Kirk Van Houten(as Kirkish Taffy), taken and eaten.
• Grampa Simpson (as Senior Mints), taken and eaten by Shauna Chalmers.
• Chocolate Rabbit, eaten by the Simpson family.
• Helen Lovejoy, impaled by Maggie (as Pazuzu).
• Julius Hibbert, stabbed in the neck by Maggie (as Pazuzu).
• Ned Flanders, choked/suffocated to death by a toy police car.
• Pazuzu (possibly), suffocated by Bart (Note: Bart was controlling him instead)
• Other Bart Simpson, accidentally strangled to death by Homer.
• Other Homer Simpson, impaled by a pair of scissors, but still alive.
• Homer Simpson, cannibalized himself for food.
• Barney Gumble, Comic Book Guy, and a horse, cannibalized for food. (deaths not seen but mentioned by Carl)

Treehouse of Horror XXIX

• Cthulhu, cooked and eaten by Homer Simpson.
• Lenny Leonard, Carl Carlson, Disco Stu, Raphael, Comic Book Guy, Marge Simpson, Bart Simpson, Homer Simpson, Lisa Simpson, Otto Mann, Clancy Wiggum, Julius Hibbert, and other residents of Springfield, had their bodies snatched (though these individuals were shown to be alive and unharmed in the Crab Nebula.)
• Clancy Wiggum (Plant Form), shot by Lou.
• Ned Flanders, despite the cameo, his conscious body was drained by the body snatchers, but in the Crab Nebula, he is shown to be still alive.
• Gary Chalmers(possibly), killed by Groundskeeper Willie for mistaking him for a plant.
• Milhouse Van Houten, Groundskeeper Willie and Maggie Simpson, possibly had their bodies snatched. (note: they were off-screen and were shown to be unharmed in the Crab Nebula.)
• Lou, choked to death by the body snatcher plant.
• Groundskeeper Willie, killed by an axe that Lisa previously killed.
• Nelson Muntz, impaled in a forklift truck by Lisa.
• Waylon Smithers, Jr., choked to death by a dinosaur's DNA head.
• Hans Moleman, squashed by a dinosaur's foot.
• Seymour Skinner, his arms were eaten by Ludodactylus Agnes and possibly died off-screen.
• Kirk Van Houten, his head was ripped off by the mutated dinosaur Jasper.
• Professor Frink(possibly), beaten to death by his other creators.
• Charles Montgomery Burns, eaten alive.
• Plane pilot(possibly), the pilot wasn't around, presumed to have died off-screen.

Treehouse of Horror XXX

• Julius Hibbert, killed by Maggie when his stethoscope choked him and was cremated in a baby incubator.
• Kearney Zzyzwicz, Shauna Chalmers and Dolph Starbeam, hung themselves from a window by Maggie's powers, they seem to make out before dying.
• Rod Flanders and Todd Flanders(possibly), possibly killed by Ned, but this was off-screen.
• Homer Simpson, Marge Simpson, Ned Flanders, all impaled by Maggie to create "Treehouse of Horror XXX".
• Üter Zörker, shown to have died in the Over Under.
• Comic Book Guy, eaten by a demogorgon which exploded into a squishie, his skeleton remained in the process.
• Carl Carlson, eaten by a demogorgon off-screen which was mentioned by Lenny.
• Lenny Leonard, eaten by a demogorgon.
• Several demogorgons, killed by Homer Simpson who used a flamethrower.
• Demogorgon Ned Flanders, killed by Homer Simpson who used a flamethrower.
• Homer Simpson, choked to death from a hot dog.
• St. Greeter, fell into Hell.
• Football Player, died some time off-screen.
• Gary Chalmers, killed off by Homer to use his body, but died from shock of the check.
• Mr. Teeny, possibly killed off by Homer to use his body.
• Moe, killed off by Homer to use his body
• Maggie Simpson, Killed off by Moe to use her body.
• Alien, cooked by Kang.
• Waylon Smithers, Jr. , his head was bitten off by Kang.
• Driver, Shot by when Mr. Burns tells him to shoot at the driver.
• Soldiers, Erased by the Infinity Gauntlet
• Charles Montgomery Burns, knocked out cold when Kang threw a can on the head, and possibly killed.

= Thanksgiving of Horror (Technically a Treehouse of Horror but Thanksgiving version)

• Maude Flanders(as turkey), head blown by the gunshot by Lou.
• Several turkeys such as Barney Gumble, Moe, Lenny, Carl, Patty, Selma and Grampa, all beheaded.

Citations

• The Simpsons Archive 'Characters on the Show' deaths The Simpsons Archive
• The Simpsons Archive 'THOH' deaths The Simpsons Archive