Phineas Flynn: The protagonist of the series. A kind hearted, fun loving young boy who loves to invent stuff to have a fun summer.
Ferb Fletcher: Phineas' silent step brother who invents stuff with Phineas.
Candace Flynn: Phineas' older sister who is obsessed with showing her mom what Phineas and Ferb invent.
Perry: Phineas' pet who is a serious, hardworking secret agent for O.W.C.A.
Dr. Heinz Doofenschmirtz: The main antagonist in the series. Perry's goofy enemy.
Major Monogram: Perry's boss who works at O.W.C.A.
Lawrence Fletcher: Ferb's goofy dad who loves antiques.
Linda Fletcher: Phineas and Candace's mom. Candace keeps trying to prove to Linda what Phineas and Ferb invent.
Isabella Garcia Shapiro: The leader of the Fireside Girls who has a crush on Phineas.
Baljeet Tjinder: A friend of Phineas and Ferb who likes school.
Buford von Stomm: A bully that is friends with Phineas and Ferb.
Carl: Major Monogram's loyal intern.
Stacy Hirano: Candace's best friend who found out that Perry is a secret agent.
Vanessa Doofenschmirtz: Dr. Doofenschmirtz's daughter. Ferb is in amor with her.
Jeremy Johnson: Candace's boyfriend.
Irving: A super big fã of Phineas and Ferb.
OTHER IMPORTANT CHARACTERS
the Fireside Girls: Isabella's group of girl scouts.
Norm: Dr. Doofenschmirtz's robot helper.
Roger Doofenschmirtz: The mayor of Danville. Dr. Doofenschmirtz's brother.
Charlene Doofenschmirtz: Vanessa's mom. Dr. Doofenschmirtz's ex-wife.
Suzy Johnson: Jeremy's sister who is rivals with Candace.
Rodney: A rival of Dr. Doofenschmirtz. The main antagonist of "Phineas and Ferb Save Summer".
Reginald Fletcher: Ferb's grandfather who was the Flying Fishmonger.
Winifred Fletcher: Ferb's grandmother.
Clyde Flynn: Phineas and Candace's grandfather.
Betty Jo Flynn: Phineas and Candace's grandmother.
Monty Monogram: Major Monogram's son. Vanessa's boyfriend.