|First Appearance||The Magic School Bus Lost in the Solar System (1990)|
|Family|| Arnold Perlstein (cousin)|
Mr. and Mrs. Perlstein (uncle and aunt)
Arizona Joan (great-aunt)
|Voiced By||Renessa Blitz|
Janet is Arnold's antagonistic, stubborn, arrogant, know-it-all yet lovely cousin. She most often tries to sabotage the class in some way to gain something for herself. She initially appeared in the book The Magic School Bus Lost in the Solar System, where it was stated she went to another school. In the TV series, she's visiting only from another class at the school, though it wasn't obvious to some of the students that Janet was lying about her class hanging the model of the solar system from the flag pole of the school.
Janet's first appearance is in "Gets Lost in Space." She starts off as an insufferable know-it-all and redeems herself in the end when Arnold freezes himself to show what would happen if she stayed on Pluto. This is her only appearance in season one.
When she returns in "Butterfly and the Bog Beast," she's back to her old manipulative self, but she's more despicable than before. She successfully turns the class against Phoebe when she points out they're playing her old school in soccer that afternoon, but at the end, she sees the error of her ways. This is her only appearance on season two.
Despite redeeming herself in "Butterfly and the Bog Beast," Janet is back to her former self in "Gets a Bright Idea," where she uses Arnold to trick the class in order to prove that a magic show would have been a better class trip than a light show. Arnold isn't too happy when he realizes she was using him for her own personal gain, but he seems to forgive her at the end, laughing off the whole thing. In "Works Out," she has no moment of redemption, though Mr. Sinew, who she was supporting in the Teacher Triathlon, congratulates Ms. Frizzle for winning. She has a brief appearance in "Goes Upstream," her last appearance in season three.
Janet's next major role isn't until "Gets Swamped," when she's debating Carlos on whether or not a new mall should be built on the wetlands. If not for the flood, she would have been successful in getting the town to vote yes on the mall. She has another brief appearance in "Sees Stars," Arnold showing embarrassment when he sees that she's the one who buys the star the class wanted to get Dorothy Ann for her birthday. In "Makes a Stink," she deliberately sabotages the class when they make a fantastic smell for the scent competition. Like in "Works Out," she doesn't have a moment of redemption.
- Janet is Arnold's only cousin, though it's unknown if they're related paternally or maternally.
- Her parents never appear in the show, but they do appear in The Magic School Bus Lost in the Solar System.
- During the producer's segment in "Butterfly and the Bog Beast," the producer described her character as "insensitive and inappropriate."
- Neptune is her favorite planet.
- Blue is her favorite color.
- In "Gets Lost in Space," her eyes appear blue in a close up.
- She's a fan of magic.
- The first coin flip Carlos ever lost was to Janet.
- She seems to be an antagonist, because of her personality.