comic-book series about a quartet of humanlike warrior turtles, which grew into an enduring multimedia franchise.

Born of a radioactive accident, raised by a talking rat, and named for Renaissance painters, the Teenage Mutant Ninja Turtles—cool-headed leader Leonardo, fun-loving Michelangelo (misspelled as “Michaelangelo” in early stories), bookish Donatello, and hot-tempered Raphael—delivered vigilante justice to the streets of New York City. There and across the world they fought gangs, aliens, and monsters, but their greatest foe was Shredder, an evil warrior who led a ninja gang called the Foot Clan.

The series and its characters were created in 1983 by cartoonists Kevin Eastman and Peter Laird, who published the first TMNT comic book (1984) in black and white, financed by a tax refund and a family loan. They also put together an inexpensive press kit and mailed it to a number of media. Their kit generated a surprising amount of coverage, and the series became one of the early success stories of the burgeoning direct-retail comic-book market.

Several years later, Eastman and Laird began a long-running relationship with licensing executive Mark Freedman, reorienting the often grim and gritty series toward the lucrative children's market. The TMNT brand spawned several popular animated television series and a handful of live-action and computer-animated movies, as well as video games, toys, and other merchandise. The franchise's popularity waned in the late 1990s, but the first decade of the 21st century saw a resurgence of interest, especially with the film TMNT (2007).