Wrestle Kingdom 9 in Tokyo Dome was a professional wrestling pay-per-view (PPV) event, produced by the New Japan Pro Wrestling (NJPW) promotion, which took place at the Tokyo Dome in Tokyo, Japan on January 4, 2015. It was the 24th January 4 Tokyo Dome Show and the first event on the 2015 NJPW schedule. The event featured ten professional wrestling matches and one pre-show match, six of which were for championships.

In the double main event, Shinsuke Nakamura successfully defended the IWGP Intercontinental Championship against Kota Ibushi, and Hiroshi Tanahashi successfully defended the IWGP Heavyweight Championship against Kazuchika Okada. A Tanahashi–Okada heavyweight title match had headlined Wrestle Kingdom 7 two years earlier and was also the main event the following year at Wrestle Kingdom 10. Although the IWGP Junior Heavyweight Tag Team Championship was successfully defended, the IWGP Tag Team Championship, IWGP Junior Heavyweight Championship and NEVER Openweight Championship changed hands. The appearance of Pro Wrestling Noah wrestlers led to a storyline in which NJPW's Suzuki-gun group began wrestling at Noah events starting the week after Wrestle Kingdom 9.