Carolyn Arnold is a member of the Arnold Family. Her twin sister is Marilyn Arnold and is one half of the Arnold Twins. She goes to Stoneybrook Elementary School. She and Marilyn celebrated her eighth birthday in Mallory and the Trouble with Twins.
Carolyn has brown hair and used to wear a silver ring on her right pinky and a beaded ID bracelet on her left wrist. She has a tiny mole under her left eye. She grows her hair long and has trendier clothes then her twin. She has become very fashion-conscious, it would kill her to wear the same thing two days in a row. Stacey McGill calls her style a mini version of hers and Claudia's style in Stacey and the Mystery at the Empty House.
In Mary Anne's Makeover, Carolyn plays out a Back to the Future fantasy. She becomes like the mad scientist from the movie and makes her own time machine in their basement. She sells tickets to take kids on a ride. They eventually give the kids back their money after Mary Anne helps her distinguish between reality and fantasy.
Marilyn watches over her when she sprains her ankle.
She plays Miles Standish in the play in Claudia and the First Thanksgiving.
- Marilyn Arnold
- James Hobart (in #51)
- Audrey Green (in LS #45)
- Haley Braddock (in #30)
- Charlotte Johanssen (in #30)
- Vanessa Pike (in #30)
- James Hobart, she gave him a 3-D card to him at the masquerade party
- Casual clothes
- Back to the Future
- Being compared to Marilyn
- Music lessons
- Fancy clothes/dresses
- Carolyn is tone deaf.
- Her room is blue and white with a cat theme.
- She wants to be a scientist.
- She carries an official-looking notebook and a pen in order to write down data.
- She is not good at keeping secrets in Mary Anne's Makeover.
- Stacey McGill says that she's a follower in Stacey's Ex-Best Friend.
- BSC #21 Mallory and the Trouble with Twins
- BSC #30 Mary Anne and the Great Romance
- BSC #60 Mary Anne's Makeover
- BSC #97 Claudia and the World's Cutest Baby