The Amazing World of Gumball characters appear in the animated sitcom The Amazing World of Gumball and revival series The Wonderfully Weird World of Gumball. The series revolves around the daily life of 12-year-old cat Gumball Watterson and his family—adoptive brother Darwin, sister Anais, and parents Nicole (née Senicourt) and Richard. Other Elmore Junior High students also have recurring roles. Creator Ben Bocquelet conceived The Amazing World of Gumball in 2007 while working for Cartoon Network Development Studio Europe, and based several of its characters on previous characters he had created for commercials.

Episodes are dictated by title as the series order is not consistent with the production order, original airing order, or order on streaming services like HBO Max.

Gumball Tristopher Watterson, born Zach Tristopher Watterson, is the main and titular protagonist of the show. He is a 12-year-old mischievous blue cat who lives with his family. He attends middle school. In "The Club", it is revealed that his middle name was supposed to be Christopher, but was actually misspelled as Tristopher ("Trisha" for short) on his birth certificate. In "The Name", he learned that his legal name was Zach and began using it, but later had his legal name changed to Gumball.

Gumball was initially presented as well-meaning, but naive. Later, he was shown as more serious, capable of logical thinking, and sarcastic. Despite occasional lapses in judgment, Gumball is loyal, straightforward, and good-natured. He is protective of his loved ones but has a large ego, often causing him to overreact.

Darwin Raglan Caspian Ahab Poseidon Nicodemus Watterson III is a 10-year-old orange goldfish who was adopted by the Watterson family. Initially given to Gumball as a pet, Darwin later sprouted legs and became a full family member. His arc begins with him as a naif, then shows him maturing. Darwin is loyal to Gumball and helps him out. He is sometimes shown exhibiting strange behavior, such as calling his adoptive parents Mr. Dad and Mrs. Mom.

Anais Errrrrr Watterson, a pink rabbit, is Gumball's precocious 4-year-old sister. She is one grade above her brothers and is often shown telling Gumball what to do. She often impatiently tags along with him as a voice of reason, but has also been shown manipulating her family to get what she wants. She sometimes exhibits childlike behavior and is shown as socially inept and incapable of forming friendships as she drives potential friends away with over-the-top clinginess. In "The Gumball Chronicles: Ancestor Act", it's revealed that her middle name is "Errrrrr", due to Richard not having enough time to pick a middle name.

Doctor Nicole Watterson (née Senicourt) is a 38-year-old cat and the mother of Gumball, Darwin, and Anais. She is a bossy, over-stressed, hot-tempered workaholic, who can be sweet. Nicole is a master martial artist, knowing Karate and winning numerous tournaments when she was young. She shows affection for and is protective of her family. Nicole is occasionally vindictive, while also resourceful and inventive. In "The Parents", it is revealed that Doctor is her first name and Nicole is her middle name.

Richard Buckley Watterson is a 38-year-old anthropomorphic pink rabbit. He is the father of Gumball, Darwin and Anais. A stay-at-home dad, he spends most of his time sleeping, watching TV, and playing video games. Richard sometimes dresses as a woman, calling himself Samantha. He is "the laziest person in Elmore". He has a large appetite and is a voracious eater. Richard often serves as a third wheel to his sons' misadventures and cares deeply for his family despite his lethargy. He is naive and frequently gets called "dumb".