The Charleston Daily Mail reports that the teacher apparently didn't know what the film was about.
Hampshire High principal Jeff Woofter says the film was shut down after 10 minutes when an assistant principal walked by and saw what they were watching.
Hampshire County school policy prohibits students from watching movies of any kind in the classroom.
It is unclear if the students or teacher will face disciplinary action.
The first "50 Shades" film opened this year on Valentine's Day weekend and became one of the biggest R-rated openings ever.
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