Jacob Finkelstein, 18, of Voorhees, NJ, has been charged with threatening to "shoot up the school" at Eastern Regional High School in Voorhees.
Police said they were informed of Finkelstein's threats last Friday after multiple students reported hearing the threats during school hours.
A search of Finklestein's home turned up no weapons, police said.
Finkelstein was arrested on Thursday and charged with one count of second degree False Public Alarm and one count of third degree Terroristic Threats related to the case.
He was moved to Camden County Correctional Facility pending a court appearance.