Bill is a boy in Derry, Maine, who struggles with a severe stutter. He acts as the natural leader for his group of friends, who refer to themselves as the Losers' Club. As an adult, he works as a successful horror novelist living in England with his actress wife, though he harbors deep suppressed trauma regarding his childhood.

Ben is an overweight, lonely child in Derry who spends much of his time reading in the public library. He possesses an innate talent for engineering and architecture, which he uses to help his friends build structures like a dam in the Barrens. As an adult, he is a wealthy, physically fit architect who travels the world alone on his private jet.

Beverly is an impoverished girl growing up in a bad part of Derry with a violently controlling father. She is an excellent shot with a slingshot and acts as a unifying presence among the boys in her social circle. As an adult, she works as a successful fashion designer in Chicago.

Richard, often called Richie, is a hyperactive boy who constantly practices ventriloquism and various comedic impressions. His inability to keep his mouth shut frequently makes him a target for local bullies. As an adult, he leverages his vocal talents into a lucrative career as a professional comedian and radio DJ.

Eddie is a physically small, nervous child whose overbearing mother constantly tells him he is fragile and sick. He never goes anywhere without his asthma aspirator and is terrified of disease. As an adult, he runs a highly successful limousine company and is married to a woman who shares his mother's smothering tendencies.

Stanley is a neat, orderly Jewish boy who enjoys birdwatching in his free time. He maintains a rigid worldview and struggles to process events that defy logic or natural laws. As an adult, he runs a successful accounting firm in Atlanta and lives a quiet life with his wife, though a sudden phone call deeply unsettles him.

Mike is a thoughtful boy growing up on a farm outside of Derry, facing severe racism from local residents. He acts as the final member to join his friend group and shares a keen interest in history. As an adult, he is the only member of his childhood friend group to remain in Derry, working as the town librarian and serving as an unofficial watchman.

Henry is a violently aggressive teenager who terrorizes younger children in Derry. Raised by an abusive, deeply prejudiced father, Henry channels his anger into sadistic acts against his peers, especially Mike Hanlon. He leads a gang of local bullies and acts as a dangerous physical threat in the town.

It is an ancient, shape-shifting entity that dwells beneath the town of Derry and awakens in cycles to feed on fear. The creature most commonly assumes the form of Pennywise the Dancing Clown to lure in children, but it can transform into whatever its victims fear the most. The entity holds a dark, pervasive influence over the entire town.

George is Bill's energetic six-year-old brother. He adores Bill and trusts him completely. His encounter with a clown in a storm drain acts as the inciting incident that drives Bill's actions for the rest of his life.

Audra is a successful movie star who is married to Bill Denbrough. She cares deeply for her husband and becomes highly concerned when he abruptly leaves their home to return to his childhood town, prompting her to follow him.

Patricia is Stanley's wife. She has shared a mostly happy life with him, though they struggle with infertility and she is aware of his unexplained bad dreams.

Myra is Eddie Kaspbrak's severely obese wife. She closely mirrors the behavior of Eddie's mother, hovering over him, worrying about his health, and attempting to manage his life.

Tom is Beverly's controlling and violently abusive husband. He deliberately seeks out vulnerable women and uses physical intimidation to maintain authority in his marriage.

Victor is one of the teenage boys who follows Henry Bowers around Derry. He acts as an enforcer for Henry's bullying, though he is generally less sadistic than Henry himself.

Belch is an unusually large teenager and a core member of Henry Bowers's gang. He uses his massive physical size to intimidate younger children and follow Henry's violent orders.

Patrick is a deeply disturbed child who believes he is the only real person in the world. He acts out his apathy by locking animals in an abandoned refrigerator at the town dump and maintaining a hidden association with Henry Bowers.

Will is Mike's father, a farmer who serves as an unofficial historian of Derry's darker past. He shares his experiences of systemic racism with his son and passes down a deep understanding of the town's history.

Butch is Henry's father and an aggressively racist man living in Derry. He harbors an intense hatred for the Hanlon family and passes his violent prejudices down to his son.

Norbert, often called Mr. Keene, runs the Center Street Drug Store in Derry. He fills Eddie's prescriptions and holds cynical knowledge about the nature of the boy's medication.

The Turtle is a massive, ancient cosmic entity that exists outside the normal universe. It stands in direct opposition to the evil entity plaguing Derry, occasionally offering subtle guidance to those fighting against the darkness.

Adrian is a young gay man living in Derry who attends the Canal Days Festival. He wears a novelty hat and faces severe harassment from local teenagers, making him an early target of the town's violence.

Don is a resident of Derry who visits the Falcon bar and attends the local festival with his partner, Adrian. He serves as a horrified witness to the town's supernatural and mundane cruelty.

Mr. Nell is an Irish police officer in Derry who patrols the areas where children play. He strictly enforces local rules but shows genuine concern for the boys' safety.

Kay is Beverly's best friend who lives in Chicago. She consistently encourages Beverly to leave her abusive marriage and tries to help her when things turn violent.