A 12-year-old cat, Gumball is a very mischievous and foolish child. He has a massive crush on Penny Fitzgerald, but neither of them are capable of properly expressing their emotions.
A 10-year-old goldfish, Darwin was once the The Wattersons' pet, but one day he grew legs and learned how to communicate. Due to his sudden introduction into the world, Darwin is very childish and naive. Darwin also enjoys helping people.
Anais is the smartest member in the family, but no one believes her because she is only a 4-year-old rabbit. She is always correcting her brothers' mistakes, which Gumball and Darwin find annoying, but deep down inside they know she is right.
The mother of Gumball, Darwin, and Anais Watterson. Nicole is the only responsible member of the family and because of this she is incredibly stressed out and is easily enraged. She is also known for taking anger management classes. Despite this, Nicole adores her family and would do truly anything for them.
The father of Gumball, Darwin and Anais Watterson. Richard is a fat, lazy rabbit who is married to Nicole Watterson. Although inattentive and extremely immature, Richard loves his family and does what he can to support them, unless it involves working.
A 12-year-old antlered-peanut whom Gumball has a massive crush on. Penny has a crush on Gumball as well, but neither of them are capable of expressing their emotions. She does not have a crush on Tobias even though Tobias has a crush on her. Leslie is her cousin.
A multicoloured, athletic kid who goes to Elmore Junior High with Gumball. He thinks he's a jock, but he's really a wimp. Like Gumball, he has a crush on Penny, but Tobias is much more confident in his abilities to woo her. However, Penny doesn't return his affection.
A sadistic old baboon who has been teaching seventh grade for over 300,000 years. Miss Simian despises Gumball and takes any opportunity to put him in detention or get him into even worse trouble. She also has many trophies. She enjoys calling Nicole a 'loser', since she was a kid.
The Robinsons' son who works many jobs around Elmore Junior High, some of them are: a bus driver, a cafeteria worker, and even in charge of the lost and found. He is friends with all the kids and he loves to goof around with them.
A Tyrannosaurus Rex and the meanest bully of Elmore Junior High. She's Jamie's best friend and takes out her limitless aggression by stomping on people.
A strange tall, fluffy creature that is the school counselor. He is a hippie, and often uses unorthodox methods when counseling, which usually don't work at all. He also seems to have a bit of a mood swinging problem.
An eyeball with wings who acts as Miss Simian's personal spy.
An effeminate flower boy who goes to Elmore Junior High. He hangs out with the girls more often than the guys, and for this reason he gives out great advice about relationships. He is also Penny's cousin.
An emo ghost who always seems to be depressed. Carrie is a social floater who talks to anyone. She misses the feelings of the living such as eating and breathing, so she will gladly possess anyone who offers their body.
A living blob of red clay that is always telling wild stories about himself to impress others. These stories are almost never true.
A simple-minded piece of burnt toast that was drafted into Tina Rex's gang against his will. Despite being a piece of toast, Anton can often be seen eating sandwiches.
A teal balloon that speaks in a high squeaky voice. Alan is one of the more popular students in Elmore Junior High. His love interest is Carmen, despite her being a cactus.
A smart cactus who is a leader among the girls. Her love interest is Alan, even though Alan is a balloon.
An eight-bit spider who can only communicate using blips and beeps, but is also able to talk in English and can also fire lasers that pixelate and blow up anything they hit.
An odd looking hybrid of a buffalo and a lion who is Tina Rex's best friend. Jamie was held back a year by Miss Simian, and shows contempt for her new classmates.
A wisecracking banana who radiates hyperactivity. He doesn't seem to possess any degree of intelligence and never realizes that the joke's usually on him.
A shy, insecure sauropod who enjoys spying on the boys in her treehouse.
A potato from the countryside with old-fashioned beliefs and mannerisms. He isn't very intelligent and is usually trying to fit in.
A multicoloured giant who is too tall to be seen in the normal field of vision. He towers over the other characters, but in reality he is very gentle and insecure. He also has intense emotions and can go on a rampage if they are set off.
An ultra-intelligent robot who is by far the smartest student in Miss Simian's class. He also has modes to defend himself with.
A spoiled-rotten cloud who is very rich, snobby, and stuck-up. One of her parents owns the Rainbow factory, where Nicole works.
A paper bear who is a hypochondriac. She spends most of her time in the Nurse's office.
A furry slug who is the principal of Elmore Junior High. He is in love with Miss Simian, and spends most of his time flirting with her instead of running the school.
A foreign exchange student who only speaks by beat boxing, which is incomprehensible to most of the people around him.
A strange looking chin creature who has a variety of obnoxious mannerisms. She also seems to enjoy eating and laughing.
A tall blue girl with multicoloured hair who is Tobias' older sister. She tends to look down upon the younger children, but may have a crush on Darwin.
An old tree woman who is the school librarian.
A brown haired, blue-skinned cyclops who sometimes appears in the series.
A living hot dog who sometimes makes cameo appearances in the background of the series.
An ice cream cone that makes cameos in Season 2 episodes in Miss Simian's class.
The Wattersons' stuck-up and irritable next-door neighbour. Gaylord despises his neighbours for their tacky lifestyle, but he is especially cruel to Gumball, who idolizes him for whatever reason.
Wife of Gaylord Robinson, whom she is just as grumpy as, and resentful towards the Wattersons as well. Margaret's only form of verbal communication is a harsh, muttering whisper.
A skinny rock-like man who works at various establishments in the city of Elmore. Larry can somehow keep up with having these jobs by working very hard. Despite this, Larry has still been fired more than a few times; although this is usually because of the Wattersons.
An elderly rabbit who is Richard's mother. She seems to be quite cranky and blunt, and only takes pleasure in watching television and kissing her grandchildren.
A living fingerprint who is a wanted criminal in Elmore. He has a thick, New York accent and has a habit of calling people "suckers."
A doughnut police officer who is quite incompetent. He is always hungry because his mouth is a large hole, which he seems to be unaware of.
A group of elderly men who can usually be seen sitting around outdoors.
A pink creature who is Larry's on-again, off-again girlfriend.
Penny's strict father, who has a strong dislike of Gumball because of the trouble that always follows him.
A blocky humanoid who works at Chanax Inc.
A living ball of newspaper who works at Chanax Inc.
A cloud-like man who works at Chanax Inc.
A slimy little man who apparently works as a literal baby sitter.
An old Lizard that fought Gumball for discount Chicken in "The Fridge".
Jealousy is a spirit that can possess anyone or anything, causing the victim to turn a shade of green and gain its face and voice, making them jealous. Jealousy possessed many people in "The Flower" .