Pictures from Chopper 11 showed students being treated at the scene by EMS workers. Officials said four students with non-serious injuries were taken to the hospital.
The rest of the students returned to the school. All of the children who couldn't be picked up by parents were taken home by another bus.
The buses were from Pathways Elementary school.
Investigators said one of buses had stopped for traffic when the second bus driver looked away, and smashed into the back of the other bus.
The driver was charged with failure to reduce speed.