An 8-year-old girl suffered a fractured skull after a rock was thrown through the window of her school bus while it was traveling along the New Jersey Turnpike, authorities reported.

Teaneck Mayor Mark Schwartz shared on Facebook, “A rock, roughly the size of a baseball, was hurled into the bus, injuring a child.”

The young victim, a third-grader whose father is a rabbi, was returning from a class trip to the Liberty Science Center in Jersey City. She attends Yeshivat Noam Orthodox Jewish Day School.

The incident occurred as the bus was exiting the turnpike at Exit 70, between 1:30 and 2:30 p.m. on Wednesday, according to Schwartz’s statement.

The girl underwent emergency surgery the following day to treat her injuries.

Schwartz, who said the girl is doing well, has offered a $5,000 reward to catch the dangerous vandal.

“Someone saw something,” he told The Post. “Someone did this. Someone threw the rock.”

The New Jersey State Police are investigating and have created a tip line at 732-441-4500, ext. 1401.

Deputy Mayor Elie Katz asked motorists to check their dash cameras.

“They may be holding some very important information for state police,” he said.

“There are kids right now who are scared to get on buses, scared to go to school,” Katz said.

“You do something horrific and heinous like this you will get caught.”

Officials cautioned that the incident appears to be random, and not a targeted antisemitic attack. The bus had no religious signage.