The Greatest Teacher

- Both are in a high school setting
- Both talk about bullying
- Both have teachers trying to change their students for the better
- Both are mystery and thriller

Another drama series that deals with bullying in a high school, along with slowly destroying a rank system among the students that's common in most bullying-centric dramas. I recommend mostly for both main leads focusing on trying to change the class they are part of, plus gaining friends along the way. Though the reasons are both very different and the roles are too (one is a teacher, the other is a transfer student) I consider 35-sai a classic drama that any should watch if they enjoy dramas that focus on school bullying and the Japanese educational system.

Teachers that are both willing to do anything to help their students, Gokusen is more of an comedy

The story of a young, idealistic teacher who enters Shirokin Gakuen in hopes of making a difference in the lives of students. However, Yamaguchi Kumiko is in for a rude awakening when she finds she will be the homeroom teacher of 3-D, the hardest class to maintain in the school. The students have multi-coloured hair and sloppy uniforms and show absolutely no respect for her.

Very similar plot.
An atypical teacher tries to change their evil students.
In Saiko no Kyoshi the teacher went back in time after her students killed her, in Ore No Sukato, the teacher is a man dressing as a women.

Both drama feature students trying to kill their teacher.
Saiko no Kyoshi is more realistic, while Sensei wo Kesu Houteishiki can be a bit over the top sometimes.

Both drama feature an adult trying to fix a messed up school.
In Saiko No Kyoshi, it's a teacher that manages to go back in time after being killed by their student, while in Ao no SP, it's a policeman assigned to work in a school.

Both drama feature school teachers trying to fix their classroom, sometimes using unconventional methods.

Both drama feature school teachers trying to fix their classroom, sometimes using unconventional methods.

Both drama feature school teachers trying to fix their classroom, sometimes using unconventional methods.

In both, a teacher is confronted with their students commiting a murder.
In Confessions, it's the teacher's daughter. She then tries to get revenge.
In Saiko No Kyoshi, it's the teacher herself, and she go back in time to prevent that.

If you like The Reluctant Preacher, you'll love The Greatest Teacher.
Both showcase fierce, flawed female teachers suddenly thrust into chaotic high schools, transforming from reluctant outsiders to bold advocates for troubled teens facing bullying and expulsions.
They confront corrupt faculty politics and systemic flaws with raw empathy, real-talk interventions, and scandalous drama over empty lectures.
Shizuka's preacher-style confrontations mirror Rina's confidence-building mysteries, as personal traumas fuel profound student growth and loyalty.
The addictive blend of comedy, heartfelt reform fantasies, and triumphant stands against harsh policies makes them perfect companions—same empowering vibe.