- Chyna Parks (China Anne McClain) is a musical prodigy who can play 47 different instruments. She is a wonderful singer and surprises people with her strong, beautiful voice. She's good at dancing, cheerleading, and drama. Never afraid of a challenge, she sees high school as an exciting place. Unfortunately, she needs to drag her new friends, Olive and Fletcher, out of their shells to experience it. She is the main protagonist of the show. She is portrayed by China Anne McClain. She is teased by Lexi because Lexi thinks Chyna is ruining her life.
- Olive Daphne Doyle (Sierra McCormick) is a human computer and became Chyna's best friend as soon as Chyna began the A.N.T Program. Olive has been Fletcher's best friend ever since they were little kids. Her gift is that she comes with an eidetic memory, which means she can also remember everything she's ever heard, seen or read. Olive is 14 years old, is fluent in Japanese as shown in "SciANTs Fair", talks very quickly, and is afraid of leprechauns, balloons, witches, zombies, birthmarks, ghosts, and curly fries. It is shown she is not scared of spiders. Her eidetic memory also makes her highly adept at video games as shown in "ReplicANT". In the episode "FraudulANT" it is shown Olive likes the soup from the most famous noodle place in San Francisco.
- Fletcher Pumpernickel Quimby (Jake Short) is an artistic genius who first meets Chyna Parks the first day of high school when she walks into the A.N.T. Farm and soon becomes her friend. Fletcher has known and been friends with Olive since they were little kids. He describes himself as kind, sweet, dependable (as revealed in StudANT Council). He developed romantic feelings for Chyna even-though fails to impress her many times. Fletcher has trouble keeping his crush a secret when he constantly keeps implying her in his art. In the episode "ReplicANT" it is heavily implied that he has an unusually long toe and claimed that Chyna was "his girl". He relies on his two best friends Chyna and Olive who along the way drag him into some trouble but in the end, he always has their backs.
- Alexis "Lexi" Reed (Stefanie Scott) is a pretty but cruel and self-centered student at Webster High and the main antagonist of the series. She was the lead in all of the musicals until Chyna showed up. She was also the freshman president of the student council and is on the cheerleading squad with Paisley. She thinks of Chyna as her competition. Lexi will do anything to be the one with the credit. For instance, in Bad RomANTs, Lexi tries so hard to get on the cover of the school newspaper(that's when she starts being so nice to Olive and Olive finally stands up to Lexi).
- Cameron O. Parks (Carlon Jeffery) (season 1-2) is Chyna's older high-schooler brother. He tries to avoid Chyna and the other ANTs due to their younger age, afraid that they will spill out one of his biggest secrets. In "The PhANTom Locker", it is mentioned he has a blankie and used to have dolls, and in "SciANTs Fair", Y8 he claims that his cell phone has rhinestones on it. Lexi mistakes him for Chyna's younger brother because he often acts much less mature than his younger sister and is almost as short. It is shown in "ReplicANT" his initials spell COP (probably because of his dad's job).
- Angus Chestnut (Aedin Mincks) is a computer genius who often runs illegal programs on his computer disguised as video games. Though he finds Chyna unattractive, he has an unrequited crush on Olive. Because of the extensive time he spends on his computer, he is quite lazy and often complains about doing basic physical tasks, such as walking in between classes. Because of this, all classes that he's chosen are on the ground floor of the school so he never has to walk up or downstairs.
- Paisley Houndstooth (Allie DeBerry) is best friends with Lexi. She is also on the cheer squad, even though she's clueless about almost every cheer. She is often confused about everything that's going on. However, she thinks different from Lexi, because she usually cares about people and animals. She's a sweet-spirited girl, but cluelessly gets roped into Lexi's schemes. Both easily fooled and free with compliments, she is treated badly by Lexi despite them being "best friends".
- Gibson (Zach Steel) is the A.N.T.’s counselor, tutor, and therapist. He is shown to be a dumb person and more of a child than an adult. He likes knitting, mahjong, and feeding pigeons. He doesn't like his grandmother's boyfriend, Bob, and in "Bad RomANTs", he has gotten back together with his childhood girlfriend despite the fact that she's in jail. He always wears a striped shirt, usually black and yellow, also he won America Needs Talent as the Great Panini.
- Darryl Parks (Finesse Mitchell), a 'highly decorated' police officer, and is Chyna's and Cameron's dad. Though he obviously loves his daughter, he can be very overprotective. He considered pulling her out of the A.N.T. program after the first episode because he thought she wasn't ready for high school. It has also been shown that he is very incompetent at his job, such as letting a purse thief run by him, while he was laughing at him for having a purse.
- Roxanne Parks (Elise Neal) is Chyna and Cameron's mom. She is a children's party entertainer. So far, she has appeared in three episodes but has been mentioned in a lot of episodes.
- Principal Susan Skidmore (Mindy Sterling) is the school principal. She's completely convinced herself that she is young and beautiful, to the point where she cannot believe her own reflection is her. She is frequently tortured by her students who only participate in the A.N.T Farm to destroy her life. She says the reason for the A.N.T Farm is for her to use their talents "to help the school get money in the bad economy" and "to exploit their gifts for her own benefit".
- Wacky the Wolf (Christian Campo) is Webster High's school mascot. He is usually seen in most episodes. He likes the A.N.T.s and often helps them out.
- Violet (Claire Engler) is a sports prodigy who has slight anger issues. She has a crush on Fletcher. She is the new A.N.T. and is very strong.
- Hippo (or Oswald) is a restaurant owner who always finds out what's in and out.
- Vanessa LaFontaine (Vanessa Morgan) was Cameron's girlfriend. In her first appearance, she was called Jean Gossimer.
- Orphans appear in SANTa's little helpers, Creative ConsultANT, and AmusemANT Park.
- Main article: Minor characters
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