Teenage Mutant Ninja Turtles, known as Geki Kame Ninja Den in Japan and Teenage Mutant Hero Turtles in Europe, is a 1989 side-scrolling action-platform game for the Nintendo Entertainment System released by Konami. In North America it was published under Konami's Ultra Games imprint in the US and the equivalent PALCOM brand in Europe and Australia.
Alongside the arcade game (also developed by Konami), it was one of the first video games based on the 1987 Teenage Mutant Ninja Turtles animated series, being released after the show's second season. The game sold more than 4 million cartridges worldwide.
The game was released for the Family Computer (Famicom) in Japan a few months earlier than the American NES version under the title Geki Kame Ninja Den (Japanese: 激亀忍者伝, which loosely translates to "Legend of the Radical Ninja Turtles"). This was the first TMNT product released in the country, predating the Japanese dub of both the first film and the animated series. Subsequent TMNT video games released in Japan kept the franchise's original title. While graphics and gameplay are virtually identical to its NES counterpart, the Japanese localization changed the plot a bit by turning April O'Neil from an acquaintance of the Turtles into Splinter's daughter.