It happened at approximately 5:15 p.m. on Millcreek Road near Graves Road in Hockessin, Delaware.
The crash involved a vehicle and a bus from the Red Clay School District with students from McKean High School on board.
Police did not say what led to the collision.
The 65-year-old driver of the vehicle was taken to Christiana Hospital after the incident. Eight students from the school bus were taken to Nemours Children's Hospital for evaluation.
Four other students and the school bus driver refused treatment.
No further information was released on this incident.