A student from Arts Academy at Benjamin Rush captured the fight on her cell phone.
The video shows the teens brawling in the aisle with one girl clearly getting the upper hand.
A person who knows the teenagers says tempers had been escalating for a few days between the two.
"I'm shocked, I really am. I have two children who ride SEPTA and it's the first I'm hearing of it," parent Shari Kapsovari said.
Kapsovari is obviously disturbed by the video, but says Rush is a great school with few problems.
The Philadelphia School District tells Action News it's aware of the fight and the school is handling it, calling the fight "atypical."
SEPTA Police Chief Tom Nestel echoed that sentiment saying school fights on SEPTA buses are rare.
"Since the school year, I think we've had two bus incidents; it's not an everyday occurrence, but when it happens, it never looks good, that's for sure," Nestel said.
SEPTA says it had concerns there may be more confrontations like this due to the districts' school mergers, but that hasn't been the case.
Extra officers were deployed and SEPTA has been working with the district.
Rush is not a merged school.
Nestel warns bus fights can be dangerous. They distract drivers and could lead to an accident.
"We are taking a very strong posture on misbehavior, those behaviors that lead up to where someone could get hurt. The school district is working with us and we are dealing with discipline within the schools and arresting people when appropriate," Nestel said.
There will be no arrests for this fight.
Neither the school nor the district would say what sort of punishment was levied.