The coach bus from Toronto-based AVM Max 200 Charter Services Inc. overturned around 7:30 a.m. when exiting interstate 80 in Wayne.
According to authorities, the New York City bound bus, chartered by a church group, landed on its side at the bottom of an embankment injuring 23 people on board.
Eight of the victims are in critical condition with non-life-threatening injuries.
Passengers say people were piled on top of each other on the floor of the bus.
"I was laying on the floor," said passenger Leona Broones. "Someone was on top of me. Someone had to pull me up off the floor."
It's not clear what caused the bus to flip over. However, the driver allegedly told state police he had been cut off by another vehicle.
The accident backed up traffic in the area for hours while law enforcement officials attended to the scene.