Phineas Flynn (Vincent Martella) and Ferb Fletcher (Thomas Sangster). They daily have extraordinary projects such as being one-hit wonders, entrepenuers, or building rollercoasters. Isabella Garcia-Shapiro (Alyson Stoner) and her troop of Fireside Girls, Buford Van Stomm (Bobby Gaylor), and Baljeet Rai (Maulik Pancholy) often join the brothers in their adventures. Candace (Ashley Tisdale), constantly attempts to expose her brothers' projects to their mom, Linda Flynn-Fletcher (Caroline Rhea), but the projects always disappear. The B-plot of the show is almost always about Perry the Platypus, a secret agent, foiling Dr. Heinz Doofenshmirtz's (Dan Povenmire) -inator machines. Doofenshirtz's thwarted plans almost always destroy or take away Phineas and Ferb's projects before their mom sees them.
The show is created by Jeff Marsh and Dan Povenmire.