The accident happened shortly after 7:00 a.m. on I-295 right at Route 9 (New Castle Avenue).
Dozens of students from the Pencader Business and Finance Charter High School, ranging in age from 14 to 18, were on the bus at the time of the accident.
Police say 37 students and the school aide were all taken to Christiana Hospital for treatment and released.
"The rear door was blocked when the bus skidded by the guard rail and the students needed to escape the bus through the escape hatches on the roof," said Master Cpl. Joe DiStefano of the DRBA Police.
School officials confirmed that none of the students were seriously injured.
There were no other vehicles involved in the incident.
Officials say it seems that the bus driver, 59-year-old Arnold Johnson of Wilmington, took the turn too fast, causing the bus to tip over.
He faces at least one charge of driving at an unsafe speed. Johnson was just hired this past summer.
"We have witnesses coming forward now and they are being interviewed and that is part of the investigation," said DiStefano.
The I-295 Northbound ramp to Route 9 South was closed for hours due to the accident.