Thomas is a teenager who arrives in the Glade confused and frightened but quickly exhibits a strong, instinctual connection to the labyrinth surrounding them. He is resourceful and determined to become a Runner, pushing against the established rules of his new environment. His sudden appearance coincides with unprecedented changes in the daily routine of the Glade.

Teresa is the only female teenager sent to the Glade, arriving just one day after Thomas. She spends her early days in a coma but quickly establishes a telepathic link with Thomas. She is bold, self-confident, and willing to challenge the boys' established social hierarchy.

Alby is the oldest and most trusted teenager in the Glade, serving as its primary leader. He enforces the community's strict laws with an iron fist to maintain stability. He has lived in the Glade for two years and carries the heavy burden of keeping the boys alive in a hostile environment.

Newt acts as Alby's second-in-command and handles the daily operations of the Glade. A former Runner who now walks with a limp, he relies on hard work and labor assignments to keep the boys grounded. He is more approachable than Alby and often serves as a mediator.

Minho is the Keeper of the Runners, responsible for mapping the labyrinth and searching for an exit. He is one of the original boys sent to the Glade. His leadership style is highly intuitive, and he does not hesitate to speak his mind or challenge authority.

Gally is a hotheaded, arrogant Glader who views himself as a crucial leader. Having survived the Changing (a painful process that restores fragmented memories), he harbors an intense, immediate hatred for Thomas. He aggressively defends the Glade's status quo.

Chuck is one of the youngest boys in the Glade and initially serves as Thomas's guide. He is talkative and enjoys playing practical jokes, masking a deep desire to return to a home and family he cannot remember. He clings to the hope of a normal life outside the walls.

Ben is a former Runner who undergoes a severe physical and mental reaction after being stung by a creature in the labyrinth. The fragmented memories he recovers during this process cause him to view Thomas as a direct threat, completely altering his personality.

Winston is the Keeper of the Blood House, responsible for raising and slaughtering livestock in the Glade. He takes a highly practical approach to his bloody work, which sometimes makes the other boys uneasy.

Zart is the Keeper of the Track-hoes, managing the farming and crop cultivation in the Glade. He is approachable and quietly does his job to ensure the community has enough food to survive.

Clint serves as one of the Med-jacks, functioning as a doctor for the teenagers. He is responsible for treating injuries and monitoring boys who undergo the severe physical stress of the Changing.

Jeff is the other primary Med-jack in the Glade. He helps treat the sick and injured, taking on the heavy responsibility of keeping the boys healthy in a highly dangerous environment.

Frypan is the cook for the Glade, managing the kitchen and keeping the boys fed. He provides a sense of normalcy through regular meals and occasionally bends the rules to save leftovers for boys working late.