The Gloucester County Prosecutor's Office said the victim died when her car collided with the bus at Route 47 and Williamstown Road around 9:00 a.m.
There were no children on board the bus at the time.
According to investigators, the bus had the green light at the intersection when the woman's Hyundai hit the bus, which then overturned.
The woman was pronounced dead at the scene.
The bus driver, and an aide, suffered only minor injuries.
The bus belonged to STA Bus Co. of Williamstown. The crash was witnessed by a Franklin Township police officer.
The identity of the woman killed is being withheld pending notification of family.
The Gloucester County Prosecutor's Office and Franklin Township Police Department are investigating.