Velma is the bespectacled resident genius of Mystery Inc. often being the one to decipher the clues and solve the crimes, she's also the Mystery Inc's android detective. She has a fascination with mysteries; her younger sister Madelyn said that she was "built with a mystery book in her hand". She is sharp-witted and often displays sarcasm and can be cocky and arrogant at times. She also seems to love secrecy, and has a bit of slyness in her character while she knows Morse Code, which she claims to have learned in Girl Scouts and knows martial arts. In the same case, she was also overly-caring of the gang, as she wanted to protect them from harm's way, despite everything they've been through. “Jinkies” is the catch-phrase what Velma uses as “oh my” or “wow” and can be thought of as an expression of surprise.

She is the fashion-loving member of Mystery Inc. Daphne's characteristic trait in the gang is her tendency to get into danger, hence earning the nickname "Danger-prone Daphne". She's confident, vain and fashion sensitive but brave. She Says jeepers as an expression or surprise.

Marcie Fleach better known as "Hot Dog Water", is a friend and former rival of Velma Dinkley. Her cruel nickname comes from her smelling like recycled water used to cook hot dogs. She has a very no-nonsense personality and shares many traits with Velma, such as skills with computer infiltration and research. She can be a very loyal person despite her cold personality and is laid back. She is good friends with Velma.

Leader of Mystery Incorporated. He has an intense love for mystery solving and building traps. His love for traps usually distracted him from noticing anything else.

Shaggy uses his catch phrase "Zoinks!" whenever he's surprised or scared, which is frequently. He can be laid back at times but is most nervous whenever there's a case.

Scoobert or "Scooby" Doo is the Great Dane mascot of Mystery Inc., and pet and best friend of Shaggy Rogers. His catch phrase, usually howled at the end of every mystery, is "Scooby-Dooby-Doo!" or "Rooby-Rooby-Roo", sometimes followed by a quirky chuckle. He has peculiar and extraordinary abilities, such as being able to talk in English, although not without pronouncing most words as if they begin with an "R", though most people are able to understand him perfectly (if they acknowledge that he can speak at all). He can also talk to other animals (mostly dogs), which comes in handy whenever the gang needs help or more information.

Velma's younger sister. Madelyn is the opposite of her big sister, Madelyn seems more extroverted, while Velma is more introverted. She does have the tendency to make rash choices.

Velma's creator and mother. She lives in the crystal cove neighborhood and is the co-owner of the Crystal Cove Spook Museum, with her husband, Dale Dinkley. She had her human daughter Madelyn.