|Kanji Name||根津 • ドーハチロ|
|Romaji Name||Nedu Dōhachiro|
|Title||Namimori Middle Science Teacher|
|Manga Debut||Chapter 4|
|Anime Debut||Episode 72|
Nezu Dohachiro is the science teacher of Tsuna, Gokudera, Yamamoto, Kyoko and Hana. He seems to believe that tests are the most important thing and always reminds his students that tests will always appear and that they have to be ready for them. He also dislikes students who get low scores, like Tsuna, and hates students who, despite not putting much effort, score high, like Gokudera.
After a science test, Nezu was mad at Tsuna, who had gotten the lowest score. When Gokudera entered the classroom, he ignored Nezu's warnings about being late again and ended up arguing. Then, Yamamoto went there to calm them down. Nezu slipped, fell down, and pretended that he had broken his arm. The next day, Nezu went to the principal, asking him to expel the three of them. While they had decided to retake the test, Tsuna and the rest overslept due to a chemical reaction from Bianchi's cooking and Haru's coffee and missed the test. The principal agreed to forgive them if they found the time capsule buried 15 years ago, which wasn't at the place it should be. After a lot of hard work, Tsuna found the capsule, but also dug up a box Nezu had buried when he was a student at the Namimori Middle School. It contained Nezu's tests; all of them had failed, and it turned out that Nezu Dohachiro wasn't good at tests at all.
- He studied at a fourth-class high school and a fifth-class university, a fact that he was lying about.
- He studied for eight years at the university until he graduated.
- In the manga, only Tsuna and Gokudera were about to get expelled and there was no such re-test. The fifteen year old capsule didn't exist. In the process of finding the capsule, a forty year old capsule came up. It contained Nezu's old exams, all of which had extremely low scores. Nezu was then fired for falsifying his academic transcripts.