Teenage Mutant Ninja Turtles (also known as Teenage Mutant Ninja Turtles: Ninja Tribunal, Teenage Mutant Ninja Turtles: Fast Forward, and TMNT: Back to the Sewer for the fifth, sixth, and seventh and final seasons of the series) is an American animated television series developed by Lloyd Goldfine. It is the second animated series and third television series in the Teenage Mutant Ninja Turtles franchise. The series premiered on February 8, 2003, as part of Fox's FoxBox programming block (later known as 4Kids TV) and ended on February 28, 2009. A sequel film, Turtles Forever, serving as both the series finale of the series and a crossover with the 1987–1996 Teenage Mutant Ninja Turtles animated series (via the plot element of the multiverse), was released on November 21, 2009.

The series was announced on May 7, 2002. It was co-produced by 4Kids Entertainment (as its first in-house animated production) and franchise creators Mirage Studios, which co-owned rights to the show, with animation provided by the studio Dong Woo.The series ran for 156 episodes over seven seasons. For its final season in 2008, the show moved from Fox to The CW. 4Kids also licensed the first 40 episodes to Cartoon Network in 2003, and Cartoon Network aired the series until 2007.