Phineas Flynn-Vincent Martella
Ferb Fletcher (step brother)-Thomas Sangster
Allison Stoner plays Isabella's voice in Phineas and Ferb.
He voiced by Thomas Sangster
Vincent Martella is the voice of Phineas Flynn on Phineas and Feb.
If you mean the voice of Phineas on Phineas and Ferb, then Vincent Martella.
Jeff "Swampy" Marsh is the voice of Major Monagram on Phineas and Ferb.
Alyson Stoner
Allison stone
The answer is Michel Musso!
Kelly Hu
The person who plays Ferb and Phineas's dad is Richard O' Brien.
Vanessa Doofenshmirtz on the show Phineas and Ferb is voice acted by Olivia Olson.
Olivia Olsen