Nippon Ichi Software, Inc. (株式会社日本一ソフトウェア, Nippon Ichi Sofutowea, known as Prism Kikaku Ltd. from July 1993 to July 1995) is a Japanese video game developer and publisher. The company was founded in 1991 and has developed several role-playing video games, most notably the Disgaea and Marl Kingdom series. Its mascot is the penguin-like Disgaea character Prinny.

NIS America, a localization and global publishing branch of the company, was founded in 2003. It originally focused solely on the North American market until being expanded to include Europe and other regions in 2007 and has also published anime.