You may be looking for:
- Valerie Frizzle - the character known as Ms. Frizzle in the original books, the 1994~97 television adaption, games, and other spin-off media for the first half of the dilogy. She is currently referred to as Professor Frizzle.
- Fiona Frizzle - Valerie’s sister; the character known as Ms. Frizzle as of The Magic School Bus Rides Again, and its rebranded Young Scientist Club kits and spin-off books. She is currently referred to as Ms. Frizzle.
- The Frizz - one of the Frizzle Fragments, the "wacky, goofy, silly side" of Ms. Frizzle.
- Fiona - one of the Frizzle Fragments, the daredevil side of Ms. Frizzle.
- Ms. Frizzle (Frizzle Fragments) - one of the Frizzle Fragments, the perfectionist side of Ms. Frizzle.