Is it illegal at a school for a student to follow a teacher on instagram?

[Annie]

Is it illegal, even if the teacher doesn't follow back?

[Rebecca]

I don't think so as long as their not following you back but you should ask your teacher or principal before you get your teacher fired

[Who, me?]

No. There is no law in place prohibiting a student from following a teacher on a public social network.
Your teacher and parents may find it weird, but it's not illegal.

[Heather]

Following your teacher on any social website is not illegal, but her higher ups might think she is unprofessional. As a teacher, rule number one with my district is to keep your Facebook, Instagrams, etc. private. However, some teachers I work with do have a personal and professional Facebook to separate their friends/family with their students/coworkers.