The teacher pulled off the girl's hijab while she was talking with her friends at the Lake Braddock High School, Virginia, the Washington Post reported.
"So my hijab was ripped off my head today," the girl tweeted. "Then he says 'Oh your hair is so pretty' and tries to play it off like it's a joke," she said.
After the incident, she ran into a restroom and called her parents. They contacted the school and a mosque. The teacher, who was not identified, told other teachers he thought the student was wearing a hoodie over the hijab. He reached to pull off the hoodie and the hijab came off, he was quoted as saying by the paper.
The Fairfax County Public Schools spokesperson, John Torre, described the teacher's action as "inappropriate and unacceptable". The teacher was placed on leave while the district investigates a complaint into the matter.