The Morning Sentinel reports, John Glowa Junior, 43, was arrested this week and charged with two counts of gross sexual assault and furnishing liquor to a minor.
Glowa is a teacher at Gardiner Area High School, but officials say the alleged victim is not a student at the school.
Police said the investigation revealed the alleged assault took place last week at a home in Mount Vernon. They said Glowa gave the girl alcohol before sexually assaulting her.
He has since been placed on administrative leave by the school and ordered not to have any contact with students.