Originally, the mutant thugs Bebop and Rocksteady were to appear in the film to fight the Turtles; they were to be martial arts soldiers that were given mutagen and turned into monstrous super-soldier mutants for the Turtles to fight. They were written out with the intent of appearing in Teenage Mutant Ninja Turtles: Out of the Shadows (2016).
This film was released on the 30th anniversary of the "Teenage Mutant Ninja Turtles" saga.
Raphael has "Mikey was here" scribbled on his shell in Japanese.
The film was originally to be called just "Ninja Turtles", but the "Teenage Mutant" part was put in to please the fans when they expressed negative feedback about that.
The VFX team incorporated the facial features of various actors into the mutants' appearances:
- Leonardo's face was based on Tom Hanks and Russell Crowe
- Raphael's face was based on Russell Crowe and Clint Eastwood (a scene where Raphael sticks his sai into his belt like a gunslinger is a homage to Eastwood)
- Donatello's face was based on Leonard Nimoy
- Michelangelo's face was based on comedian Bill Murray
- and Splinter's face was based on Japanese actor Toshirô Mifune, who had played various samurai in his career (Splinter even has a chonmage haircut like Mifune usually wore in his samurai role).
Kevin Eastman: creator of "Ninja Turtles", a doctor. Eastman was also brought on as consultant for the film, and provided artwork for the opening animated montage.
Behati Prinsloo: Victoria's secret angel in the end credits in a Victoria's Secret billboard ad, which the turtles use to hide themselves from the civilians and blend in with their surroundings.