Tetsuya Naito (内藤哲也, Naitō Tetsuya; born June 22, 1982) is a Japanese professional wrestler. He is working as a freelancer, primarily on the independent circuit and Pro Wrestling Noah, where he is one-half on the reigning GHC Tag Team Champions with Bushi. He is also the leader of Los Tranquilos de Japon. He is best known for his 21-year run in New Japan Pro-Wrestling (NJPW) from 2004 to 2025, and is largely regarded as one of the greatest and most popular wrestlers in the company's history, where he was a five-time world champion.

Naito began training for a professional wrestling career in 2000, initially under Animal Hamaguchi before joining NJPW in 2004, where he underwent further training and progressively rose to main event status. Although NJPW aimed to establish him as a top star by 2014, his clean cut babyface persona caused significant fan backlash, leading to his planned main event match at Wrestle Kingdom, NJPW's biggest event, to be demoted. This, and a stay in the Mexican stable Los Ingobernables through NJPW's partnership with Consejo Mundial de Lucha Libre (CMLL), would lead Naito to reinvent himself as an antihero leading his own stable, Los Ingobernables de Japon. Despite its villainous tendencies, this new gimmick immediately led him to new heights of popularity, and he would win the company's top prize, the IWGP Heavyweight Championship, thrice, and its direct successor, the IWGP World Heavyweight Championship, twice, while finally main-eventing Wrestle Kingdom five separate times. He departed NJPW in 2025 and proceed to continue to work as a freelancer on the independent scene and for Pro Wrestling Noah, where formed the spin-off stable Los Tranquilos de Japon.

In NJPW, Naito is also the winner of the 2013, 2017 and 2023 editions of the G1 Climax, NJPW's premier singles tournament, and of the 2016 New Japan Cup. Other accomplishments include being the first person to hold the IWGP Heavyweight and Intercontinental Championships at the same time, a feat he accomplished twice, and being together with partner Yujiro Takahashi as No Limit the first team to have held both the company's heavyweight and junior heavyweight tag titles. He was awarded Tokyo Sports's MVP Award, the publication's highest honor, in 2016, 2017, 2020, and 2023.

Naito began training for a professional wrestling career in 2000, initially under Animal Hamaguchi. In 2004 Naito won the "Takeda Dojo Submission" tournament, which landed him a contract with New Japan Pro-Wrestling (NJPW) to train in their dojo.

After a year in NJPW's Dojo on November 3, 2005, Naito passed a public audition held by NJPW in Korakuen Hall, graduating from the dojo and earning a spot on the promotion's roster. After half a year of further training, Naito wrestled his debut match on May 27, 2006, losing to Takashi Uwano. He picked up his first win on October 29 over Mitsuhide Hirasawa. In 2007, Naito participated in the 2007 Best of the Super Juniors tournament, replacing a wrestler who was unable to compete due to injuries. Tetsuya finished last in Block B, earning four points by defeating Gedo and El Samurai, losing the other four matches in his block.

In February 2008, Naito formed a tag team with fellow rookie Yujiro Takahashi called No Limit. In March, the two went to fifteen-minute time limit draws with former IWGP Junior Heavyweight Tag Team Championship teams such as Koji Kanemoto and Wataru Inoue, and Minoru and Prince Devitt, and Takahashi pinned veteran Super Strong Machine in a trios match. All of this led to a junior tag title challenge for the duo, facing Machine's Legend stablemates Jyushin Thunder Liger and Akira, in which No Limit came up short when Akira pinned Naito.

In May 2008, Naito and Takahashi underwent a five-match series with some of New Japan's top tag teams, dubbed "No Limit Generation Smash", held in the various Zepp clubs across Japan. The teams included Jado and Gedo, Togi Makabe and Toru Yano, Wataru Inoue and Koji Kanemoto, Shinsuke Nakamura and Hirooki Goto, and Yuji Nagata and Manabu Nakanishi. No Limit lost all five matches. A special sixth match in the series took place in Zero1 on May 29, 2008, Naito and Takahashi defeated Zero1's Osamu Namiguchi and Shito Ueda. In July, Naito and Takahashi participated in a single-elimination tournament to decide the new holder of the recently vacated IWGP Junior Heavyweight title. Naito lost to Takahashi in the first round of the tournament. On October 13, 2008, at Destruction '08, Naito and Takahashi defeated Devitt and Minoru to win the IWGP Junior Heavyweight Tag Team Championship. On January 4, 2009, at Wrestle Kingdom III, the Motor City Machine Guns (Alex Shelley and Chris Sabin) defeated them to win the tag team title. Shortly after losing the IWGP Junior Heavyweight Tag Team Championship Naito and Takahashi traveled to North America for a "developmental tour", something often done with young Japanese wrestlers to expose them to other styles of wrestling and help them develop into better wrestlers.

On December 5, 2009, NJPW announced that Naito and Takahashi were returning to Japan as part of their annual January 4 Tokyo Dome Show, Wrestle Kingdom IV. At the event Naito and Takahashi defeated Team 3D (Brother Ray and Brother Devon) and Bad Intentions (Giant Bernard and Karl Anderson) in a three-way hardcore match to win the IWGP Tag Team Championship. No Limit had their first title defense on February 14, 2010, defeating El Texano Jr. and El Terrible to retain the title. On April 4 at New Dimension No Limit joined New Japan's top heel stable Chaos, led by the IWGP Heavyweight Champion Shinsuke Nakamura. On May 3, 2010, at Wrestling Dontaku 2010 Naito and Takahashi lost the IWGP Tag Team Championship to Yuji Nagata and Wataru Inoue of Seigigun in a three-way match, which also included Bad Intentions.