Female, protagonist, Dipper's twin sister. Bright, positive, quirky, and social. Long brown hair, colorful sweaters. She has a pet pig named Waddles and loves making friends. She maintains a positive attitude even in the face of crisis.

Male, owner of the Mystery Shack. Cheerful, con-artist tendencies, loves money, cherishes family. Gray hair, black suit, red fez. He runs the Mystery Shack for tourists. While he appears to only care about money, he is someone who would risk his life for his family. In truth, he spent decades researching the dimensional portal to rescue his twin brother, Stanford Pines.

Male (Demon), a high-dimensional being in the shape of a triangle. Cheerful, insane, cunning, and cruel. Yellow triangular body, single eye, top hat, and cane. A demon who moves between dreams and the mental world. He can manipulate reality by making deals with people and plunges the world into chaos by triggering Weirdmageddon. He is one of the most powerful beings in Gravity Falls.

Male, Mystery Shack employee. Lazy, humorous, and pure-hearted. Green hat, green t-shirt. He isn't the most efficient worker, but he helps his friends in times of crisis.

Male, scientist, author of the journals. Intellectual, calm, and cautious. White hair, glasses, long coat, six fingers. A scholar who researched the supernatural phenomena of Gravity Falls. He wrote Journals 1-3 and is the most aware of the danger Bill Cipher poses.

Male, protagonist, Mabel's twin brother. Smart, curious, cautious, and brave. Brown hair, blue vest, wears a hat. His goal is to uncover the mysteries of Gravity Falls, and he investigates supernatural events after discovering Journal 3.

Female, heiress of the Northwest family. Haughty, high self-esteem, undergoes character growth. Blonde hair, luxurious clothing. Initially arrogant, her personality gradually changes as she experiences events with Dipper.

Female, Mystery Shack employee. Easygoing, brave, and relaxed. Long red hair, flannel shirt, hat. Dipper's first crush. She possesses excellent survival skills and combat instincts.

Male, inventor, former scientist. Eccentric, quirky, insane, cowardly but kind-hearted. Long white beard, messy white hair, old overalls. A genius scientist who once researched supernatural phenomena with Stanford Pines. Due to the shock experienced during the portal experiments, he repeatedly used a memory-erasing machine, which left his mind unstable as a side effect. He currently lives in Gravity Falls collecting junk and machinery, but his brilliant invention skills remain intact. He helps Dipper's group with great courage and technical prowess during crises.

Male, young con artist. Cunning, obsessive, and greedy. White hair, blue suit. He deceives people by pretending to be a psychic. He once tried to take over the Mystery Shack and sought the journals.