It happened around 2:45 p.m. Monday on Edgewood Road near Merrick Road, behind the Hamilton Marketplace shopping center.
The bus driver, 69-year-old Jeanette Guerra, told police she was traveling south on Merrick, approaching the New Jersey Turnpike overpass, when a deer ran onto the road.
Guerra says she swerved to avoid hitting the deer and lost control of the bus.
The bus, from St. Gregory the Great Academy in Hamilton Square, N.J., plunged sideways down a gulley and came to rest on the driver's side.
The driver and all 14 students onboard - ranging from 8 to 13 years old - were able to get out safely.
Seven children and Guerra were taken to Robert Wood Johnson Hospital for minor injuries.
By Monday night, six of those children and Guerra had been treated and released.
The seventh child was transferred to the Bristol-Myers Squibb Children's Hospital at Robert Wood Johnson University Hospital in New Brunswick for observation.
That child was listed in good condition Tuesday morning.
The other children on the bus were released to their parents at the scene.
Action News spoke with 6th grader Christian DeLorenzo, one of the students on the bus.
"All of a sudden I saw the first swerve and it was on one tire and flipped into the ditch," Christian said.
"You could imagine as a parent, you're very scared. Fortunately, Christian had his seatbelt on. That's the most important thing that he's okay and we hope the other children that got hurt are okay. That's all that matters," said Christian's father, Joe DeLorenzo.
Authorities told Action News that students normally would have been off for the President's Day holiday, but the school was making up a day missed because of Hurricane Sandy.
The bus was towed from the gulley Monday evening.
The accident remained under investigation. Any witnesses were being asked to contact the Hamilton Police Traffic Unit at 609-581-4024.