Gloucester County Prosecutor Sean Dalton said the 16-year-old boy, a student at Clearview Regional High School in Mullica Hills, was charged as a juvenile Monday following an investigation, KYW-TV in Philadelphia reported.
The television station did not specify the charges.
"Thank God because in this day and age, we should be able to find out who these people are," Dana Minore, a parent, said.
The teen created a Facebook page using a phony name and started threatening students, investigators said.
"The postings range from blasting people in the school, acts of physical violence and other disturbing comments," Dalton said.
"We're obviously disappointed he was involved in this type of activity," said the school's superintendent, John Horchack III.
Police said the teen is also suspected of falsely reporting a shooting at a Mantua restaurant, and police said he harassed people on the phone.
The boy didn't say what motivated his alleged actions, the television station said.