Pretty sure this isn't allowed. Talk to an administrator. Now.

Alright. So you may have been less than stellar in one class. So what? With your remaining grades being above 90%, we all know you are a smart kid. Sadly, many of us have had parents like yours. Craziness, I know... We know that the struggle is real. So keep your eyes on the prize. Finish school, turn 18, and get out. Move to the college/university/city that is far enough away that your parents can't continue stressing you out, and see if you can get scholarships and/or other means of financial support. As for today, there are a few options. Your best bet is probably going forward to the principals office. You are still a top student, despite one rough grade. These people should listen to you. Sharing about the struggles with your domineering parents and your teacher who is now freaking out should help take that burden off your shoulders. Teacher was irresponsible and unprofessional in making those threats, absolutely. But from what you say, your parents have a whole other set of issues, and today may have simply been the straw that broke the camels back. The principal will talk to them all, and likely discipline accordingly. You are young. As you wait for this to settle, get back to studying so that you can pack your things and get out as soon as possible with a solid strategy and plan. Good luck OP!

Welcome to the educational system, where the rules don't make sense and your grades don't seem to matter.

Talk to your principal - they'll straighten this shit out real quick. I once got a bad grade in middle school bc I took too long bringing back my signed interim report card. My dad went to the superintendent (small school system), & long story short, teachers can't give grades for that shit anymore.

Sounds like you gotta forge that signature

Are you Indian or Asian or something?

Either your parents are Asian or they're just not parents. Have the teacher call the parents and let them explain why there's no signature.

I don't know how it works where you live, but where I'm from its not just the teachers choice to hold back a child. It involves every teacher who teaches you, a guidance counselor, the principle and your parents. I see the issue with your parents but there are other adults who should be involved. Your parents refusal isn't grounds for holding you back if you have good grades. Any adult with some sense will see this. I can see how your teacher may think you didn't show your parents, but it's not a bad grade, why wouldn't you (again logically, your parents are a bit off) show them that grade? And your teacher hasn't tried any communication with your parents? Somethings off here. When I had a teacher loose my report card, she showed up at my house. I had turned it it, signed, and she lost it. She was so b*tchy about it, saying I lost it and it was my fault and threatening detention. I was 10 and turned it in. The principal got involved and they printed a new one. Guess what b*tch teacher found in her desk at the end of the year? Never did apologize. I still don't shop at her husband's local store. Petty, I know, but grudges run deep. An 'ohh, sorry' would have went so far.

OP, your teacher is just trying to scare you, he cannot fail you for lack of parent-teacher communication, as that is the parents and teachers responsibility, and you are a studen, a minor I assume, with little control over how the adults in your life choose to act. Sorry OP but things get better, at least in that aspect, as u get older. 10 years out of high school myself, and I 2ouldnt go back to those days for 1 billion dollars. lol. KEEP UR HEAD UP OP!!

Take it to the principal. The teacher should not be able to fail/hold you back because of a lack of communication between them and the parents.