Mobile Suit Gundam 00 (機動戦士ガンダム00（ダブルオー）, Kidō Senshi Gandamu Daburu Ō, Mobile Suit Gundam Double-O) is a Japanese anime television series, the eleventh installment in Sunrise studio's long-running Gundam franchise comprising two seasons. The series is set on a futuristic Earth and is centered on the exploits of the fictional paramilitary organization Celestial Being and its efforts to rid the world of war and conflict with a series of unique and extremely advanced mecha mobile suits known as "Gundams". Unlike the previous installments, the timeline that this series takes place in corresponds to the real life Gregorian calendar, in this case Anno Domini (AD).

It is directed by Seiji Mizushima and written by Yōsuke Kuroda, and features character designs by Yun Kōga. The 25-episode season was officially announced by Sunrise during a 15-second trailer on June 2, 2007. The series aired on the Mainichi Broadcasting System, Tokyo Broadcasting System and its affiliated JNN stations from October 5, 2007 to March 29, 2008. The second season began on October 5, 2008 and concluded on March 29, 2009. A film sequel, titled Mobile Suit Gundam 00 the Movie: A Wakening of the Trailblazer, premiered in Japan on September 18, 2010 and was released on DVD and Blu-ray on December 25, 2010, in Japan. Mobile Suit Gundam 00 is the first Gundam television series to be animated in widescreen and in high-definition.