Most are returning characters from Phineas and Ferb:
Phineas Flynn-Vincent Martella
Ferb Fletcher-Thomas Sangster
Isabella Garcia-Shapiro-Alyson Stoner
Baljeet Patel-Maulik Pancholy
Claire Bernix-Madison Pettis (New Character, acts like Candace; "Teacher, Phineas and Ferb are building....")
Candace Flynn-Ashley Tisdale
Jeremy Johnson-Mitchel Musso
Stacy Hirano-Kelly Hu
Mr. Jariwoski-Dan Povenmire (New Character, Phineas and Ferb's teacher)
Mrs. Maria-Gonzalos-Caroline Rhea (New Character, Candace and Stacy's teacher)
Heinz Doofenshmirtz- Dan Povenmire
- Phineas and Ferb are in 5th grade, and Candace is in 10th. Phineas and Ferb attend Danville Elemantary while Candace atends Danville HIgh.
- All new characters listed above are voiced by returning voice actors from Phineas and Ferb; Madison Pettits voices Adyson, Dan Povenmire voices Dr. Doofensmirtz and Caroline Rhea voices Linda Flynn.
- The new theme song "School Dayz" follows the same idea as the orignal. "There are so many days in a school year, until summer comes again, so the annual problem for kids of all nations, is finding a way to have fun, like maybe...". The orignal theme was to be "Today I'm Gonna Get Good Grades" but Dan and Jeff decided to invent a brand new song about having fun at school.
- This series happens after their summer of building and before and after the Christmas Special. That's why the begining of the series (Sept,Oct,Nov) happen in the fall and Jan, Feb, and begining of March happen in the winter. (March, Apr, May, June happen in spring).
- It´s discover that, during the "school time" Heinz Doofenshmirtz is not an evil scientist. he is just a teacher, and Perry is on holidays until the next june