Note:
I have received a number of emails from concerned readers about these lyrics. In fact in the United States the title of the show is called "Teenage Mutant Ninja Turtles". It was changed in the UK to "Teenage Mutant Hero Turtles" to stop kids hitting each other.with homemade nunchuckers and copying the ninja way (the suits thought that it was a bad influence). So for the sake of completeness I have now included the US version of the lyrics below.

UK Version:

Teenage Mutant Hero Turtles
Teenage Mutant Hero Turtles
Teenage Mutant Hero Turtles
Heroes in a half-shell - Turtle Power

They’re the world’s most fearsome fighting teens, (we're really hip)
They’re heroes in a half-shell, and they’re green, (hey! get a grip!)
When the evil Shredder attacks,
These turtles boys don't cut him no slack.

Teenage Mutant Hero Turtles,
Teenage Mutant Hero Turtles.

Splinter taught them to be fighting teens, (he's a radical rat)
Leonardo leads, Donatello does machine's, (that's a fact chap).
Raphael is cool but crude, (gimme' a break!)
Michaelangelo is a party dude (Hurray!!).

Teenage Mutant Hero Turtles,
Teenage Mutant Hero Turtles.
Teenage Mutant Hero Turtles.
Heroes in a half shell,
Turtle power!

US Version:

Teenage Mutant Ninja Turtles
Teenage Mutant Ninja Turtles
Teenage Mutant Ninja Turtles
Heroes in a half-shell - Turtle Power

They’re the world’s most fearsome fighting teens (we're really hip)
They’re heroes in a half shell and they’re green, (hey! get a grip!)
When the evil Shredder attacks,
These turtles boys don't cut him no slack.

Teenage Mutant Ninja Turtles,
Teenage Mutant Ninja Turtles.

Splinter taught them to be ninja teens (he's a radical rat)
Leonardo leads, Donatello does machines (that's a fact chap)
Raphael is cool but crude, (gimme' a break)
Michaelangelo is a party dude (Hurray!!)

Teenage Mutant Ninja Turtles,
Teenage Mutant Ninja Turtles.
Teenage Mutant Ninja Turtles.
Heroes in a half shell,
Turtle power!