County prosecutors say Erica DePalo, a 33-year-old Montclair resident who teaches English at West Orange High School, was charged with aggravated sexual assault, sexual assault and child endangerment.
Her bail was set at $100,000, and it was not known Saturday if she had retained an attorney.
Prosecutors say the relationship between DePalo and the student in her honors English class started in June and ended this week.
They did not say how they learned of the alleged relationship.
Interim West Orange Schools Superintendent James O'Neill says DePalo has been suspended "indefinitely."
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