This season transitioned the franchise into with a heavy focus on character growth and humor.

: Shredder, Krang, Bebop, and Rocksteady are introduced as the primary antagonists operating out of the Technodrome .

: Critics from Rotten Tomatoes note it as "hip, playful and witty," though it is famously more comedic and campy than the original Mirage comics. 2003 Animated Series (4Kids)

: It introduces the mutation of Hamato Yoshi into Splinter and the Turtles' first meeting with reporter April O'Neil .

: It features a darker aesthetic with heavy shadows and no pupils in the Turtles' masks.

: Major arcs include the "Notes from the Underground" trilogy and "The Shredder Strikes Back".