Team Ninja (Japanese: チームニンジャ) is a Japanese video game development studio of Koei Tecmo, founded in 1995. It was formerly led by Tomonobu Itagaki and is best known for the Ninja Gaiden action-adventure game series and the Dead or Alive fighting game series.
Team Ninja was originally formed by Itagaki from game designers working at Tecmo, specifically for the purpose of creating the home versions of the fighting game Dead or Alive and its sequel, Dead or Alive 2. In 2008, the action-adventure game Ninja Gaiden II for the Xbox 360 was published by Microsoft Game Studios, making it the first game created by Team Ninja to not be published by Tecmo; Tecmo Koei later released an enhanced version of Ninja Gaiden II on the PlayStation 3 as Ninja Gaiden Sigma 2.
On June 3, 2008, Dead or Alive creator Tomonobu Itagaki announced that he would be leaving Tecmo and Team Ninja on July 1, 2008, citing difficulties with the company. In the same statement announcing his resignation, he also announced that he was filing a lawsuit against Tecmo over unpaid bonuses for his work on Dead or Alive 4 for the Xbox 360. It was later reported that he was fired from Tecmo on June 18, 2008 in retaliation for his lawsuit. Many of his colleagues at Team Ninja quit as well to join him at his new game development team, Valhalla Game Studios. Some ex-Team Ninja members also helped with Ubisoft's Teenage Mutant Ninja Turtles: Smash-Up.