The crash happened at the Simmons Elementary School at 411 Babylon Road in Horsham.
School district officials say that, for an unknown reason, the bus struck the back of the school van.
Approximately 24 students were on the bus, and seven children were in the van at the time. A staff member from Simmons Elementary was also on the van, the district said.
Everyone was checked out by medics on the scene, and five children and two staff members were eventually taken to Abington Memorial Hospital.
Horsham Police are investigating the crash.