Mrs. Jewls is the quirky but genuinely caring teacher of the 30th-story classroom at Wayside School. She initially mistakes her students for monkeys due to their cute behavior. Despite her bizarre teaching methods and strict reliance on an arbitrary discipline list, she actively helps her students overcome personal and academic challenges.

Mrs. Gorf is the original teacher of the 30th-story classroom. She harbors a deep disdain for children and punishes them for the slightest mistakes. She possesses the supernatural ability to turn students into apples by wiggling her ears and sticking out her tongue, a power she uses frequently to empty her classroom.

Louis is the yard teacher and playground supervisor who sports a red face and a multicolored mustache. He serves as an authority figure but acts more like a peer to the students, joining their games and occasionally fueling the school's absurd situations. He also functions as the in-universe author of the stories, chronicling the daily events at Wayside.

Todd is a quiet, well-behaved student who constantly finds himself in trouble. Despite his best efforts to remain silent, he frequently ends up on the class discipline list, resulting in him being sent home early on the kindergarten bus as a recurring punishment.

Joy is a student with a big mouth who constantly chews gum. She frequently instigates trouble and breaks rules but manages to evade punishment while other students take the blame for her actions.

Joe is a curly-haired student who struggles to count sequentially. Despite his inability to count properly, he consistently arrives at the correct answer through sheer luck or chance during math exercises.

Sharie is a student notorious for falling asleep during class. Because she rests so much at school, she finds herself unable to sleep at night. She eventually falls out of the classroom window during a deep slumber.

Bebe is the fastest artist in the 30th-story classroom. She prioritizes quantity over quality, drawing hundreds of pictures in a single hour with the help of a classmate who hands her fresh supplies.

Calvin acts as Bebe's dedicated art assistant, rapidly handing her paper and crayons so she can maintain her drawing speed. He is later tasked with the impossible mission of delivering a note to a nonexistent teacher on a nonexistent floor.

Myron holds the title of class president, a role entirely dedicated to turning the classroom lights on and off. He briefly abandons his post to rescue a classmate's dog, resulting in his demotion.

Dana is a student with beautiful eyes and glasses. She suffers from an overwhelming number of itchy mosquito bites all over her body, an ailment she attempts to cure using arithmetic.

Maurecia is an incredibly popular student whom everyone likes, though she claims to like no one in return. Her sole passion is eating ice cream until she eventually grows tired of all traditional flavors.

Paul sits in the very back of the classroom and battles a constant, overwhelming compulsion to pull the pigtails of the girl sitting directly in front of him. He attempts to manipulate the classroom discipline rules to indulge his habit without suffering serious consequences.

Leslie is a student who believes her ten toes are completely useless. She actively tries to figure out a practical purpose for them and considers selling them to the playground supervisor.

Jason has the second-largest mouth in the classroom. After reporting a classmate for misbehavior, he suffers an unusual and highly physical consequence when he becomes securely glued to his chair.

Rondi is a student missing her two front teeth. She becomes immensely frustrated and angry when her classmates continually compliment her nonexistent teeth and imaginary clothing items.

Sammy is a deeply unpleasant new student who enters the 30th-story classroom covered in multiple layers of raincoats. He exudes a terrible odor and shouts insults at the teacher and his peers when asked to remove his wet clothing.

Deedee is a student who greatly prefers recess over spelling lessons. Because she attends class on the 30th floor, she consistently misses out on the best playground equipment and devises elaborate schemes to reach the yard early.

DJ is a student who constantly wears a huge, infectious smile. His unexplained happiness spreads rapidly throughout the classroom, prompting his classmates to try and guess the reason for his excellent mood.

John is a highly intelligent student who has a peculiar reading habit: he can only read text when it is positioned upside down. He eventually learns to stand on his head to read the chalkboard properly.

Kathy is a deeply pessimistic girl who intensely dislikes everyone she meets. She assumes that all of her peers despise her in return, and she often behaves in ways that guarantee negative outcomes for herself.

Ron is a student eager to play sports but is repeatedly excluded by his classmates due to his complete lack of athletic skill. When he finally gets to play, his team suffers catastrophic losses.

Eric Bacon is one of three Erics in the 30th-story classroom. Despite being the skinniest boy in the class, he receives the nickname "Fatso" due to assumptions based entirely on the physical traits of the other Erics.

Eric Fry is a highly muscular athlete who shares a first name with two unathletic peers. Because of this association, the other students mistakenly presume he is clumsy and nickname him "Butterfingers."

Eric Ovens is genuinely the nicest student in the entire class. Unfortunately, because the other two Erics act mean in response to their unfair nicknames, the class assumes Eric Ovens is also mean and calls him "Crabapple."

Allison is a pretty girl who finds herself continuously giving away her personal possessions to various school authority figures out of a sense of obligation. She threatens violence against boys who tease her.

Dameon is a student who frequently acts as a messenger. He once runs up and down thirty flights of stairs multiple times to relay trivial questions, ultimately causing him to miss out on a classroom activity.

Jenny is a student who mistakenly arrives at the school on a Saturday. She has a highly confusing and intimidating encounter in the empty classroom with strangers asking bizarre questions.

Terrence is a good athlete but a terrible sport. He actively ruins recess for the other students by repeatedly kicking the ball over the school fence until there is nothing left to play with.

Nancy is a quiet and shy boy who intensely hates his first name because he considers it to be a girl's name. His embarrassment causes him to speak very little until he meets someone experiencing a similar problem.

Mac is a female student from the 23rd floor of Wayside School. Like her friend Nancy, she intensely dislikes her given name because she feels it does not suit her gender, prompting a unique exchange between the two students.

Stephen is a green-haired boy who takes over as class president. He celebrates Halloween on the wrong day by wearing a goblin costume to school, drawing mockery from his peers until an unusual event validates his choice.

Miss Zarves is the teacher assigned to the 19th story. Because the builder forgot to include the 19th floor when constructing Wayside School, neither she nor her classroom actually exists.

Miss Mush is the lunch teacher at Wayside School. She prepares highly questionable and unappetizing meals for the students, including her infamous porridge, and occasionally asks students to share their personal snacks with her.