Erica DePalo faces aggravated sexual assault, sexual assault and child endangerment charges.
Prosecutors say the 33-year-old Montclair resident had a relationship with a student in her honors English class. They say the affair started in June and ended recently.
School officials say DePalo has been indefinitely suspended from her job teaching English at West Orange High School.
Prosecutors have not said how they learned of the alleged relationship.
DePalo's bail has been set at $100,000. It's not clear if she had retained an attorney.
She's due in court Wednesday morning in Newark.