Police in Mahway say the accident occured at approximately 5 p.m. near the intersection of East Crescent Avenue and Masonicus Road.
The school bus, carrying four students from Bergen Academies, was making a left turn when a Lexus hit the rear side of the bus, which caused it to go into a spin and collide with a tree down the road.
The four children were all transported to local hospitals with non-life threatening injuries.
The bus driver, a 57-year-old woman, was taken to Hackensack Hospital, while the driver of the Lexus, a 25-year-old woman, was taken to Good Samaritan Hospital with facial injuries.
No summonses have been issued at this time.