IWGP World Heavyweight Championship

The IWGP World Heavyweight Championship (IWGP世界ヘビー級王座) is a professional wrestling world heavyweight championship owned by the New Japan Pro-Wrestling (NJPW) promotion. "IWGP" is the acronym of NJPW's governing body, the International Wrestling Grand Prix (インターナショナル・レスリング・グラン・プリ). The championship was created on March 1, 2021, by the unification of the IWGP Heavyweight Championship and the IWGP Intercontinental Championship. The current champion is Tetsuya Naito, who is in his record-tying second reign.

History
In 2019, when he was IWGP Intercontinental Champion, Tetsuya Naito declared his intention of making history by becoming the first to hold the IWGP Heavyweight Championship and the Intercontinental Championship at the same time. By the end of the year, Jay White, who had won the Intercontinental Championship from Naito, and Kota Ibushi, who was the next challenger for the Heavyweight Championship, also expressed the same desire. After a fan vote, it was decided that Naito, White, Ibushi, and Heavyweight Champion Kazuchika Okada would compete at Wrestle Kingdom 14 on January 4–5, 2020, where one would end up with both titles. Naito achieved the feat to become the first "Double Champion" and the two titles were defended together since (apart from one time). During 2020, Naito said his original intention was for the titles to be defended separately. He requested for this, or otherwise for the titles to be unified, but no change happened.

After Ibushi won the titles from Naito at Wrestle Kingdom 15 on January 4, 2021, he expressed his desire for the titles to be unified. On March 1, 2021, with Ibushi still champion, the unification of the titles to create the new IWGP World Heavyweight Championship was officially announced, with Ibushi as the inaugural World Heavyweight Champion. After the announcement, Ibushi, who was scheduled to face El Desperado at the NJPW 49th Anniversary Show on March 4, 2021 in a non-title match, requested for the match to be for the Double Championship. His request was granted with the title unification delayed until after the match, of which the winner would be final Double Champion and, therefore, the inaugural World Heavyweight Champion. Ibushi won the match.

With the announcement of the new championship was the announcement of a new championship belt. Until the new belt was ready, Ibushi continued to hold the old IWGP Heavyweight and IWGP Intercontinental Championship belts. The new belt was eventually revealed and presented to the champion Ibushi in a presentation ceremony on March 30, 2021. Its design incorporated the past belt designs of the two old titles.

Reigns
As of July 29, 2024, there have been ten reigns shared among eight wrestlers with one vacancy. Kota Ibushi was the inaugural champion. Sanada's singular reign is the longest at 271 days, while Ibushi's reign is the shortest at 31 days. Tetsuya Naito is the oldest champion when he won it at 41 years old, while Will Ospreay is the youngest, winning it at 27 years old. Naito and Kazuchika Okada are tied with the most reigns at two.

Tetsuya Naito is the current champion in his second reign. He defeated Jon Moxley at Forbidden Door in Elmont, New York on June 30, 2024.

Combined reigns
As of July 29, 2024.