If you provide more details (decade, language, plot), I can narrow it down. Otherwise, the closest match might be:

— though that’s not a school teacher movie; it’s a crime/drama.

To give you a clear answer: Most likely you are mixing up “Lara” from “Lara and the Teacher” (obscure) or a foreign film.

The most likely answer is:

It sounds like you’re looking for a movie about a (or a similar-sounding name).