It happened around 11:45 p.m. Saturday on Route 100 near Farmington Avenue in Upper Pottsgrove Township, Montgomery County.
Police say the driver of an SUV lost control, struck a guard rail, then flipped over.
Investigators say the students who died were in the rear seat and were ejected from the vehicle.
Those victims have been identified as Pottstown Senior High School sophomores Breanne Brothers and Andrea Antonio-Harris. . Friends describe Brothers and Antonio-Harris as vibrant young women who treated everyone with kindness.
A total of six people were in the SUV. The four survivors are being treated at Reading Hospital.
Police say the driver was a 18 year old man, and the front passenger was a 17-year-old girl. Besides the two girls who were killed, a 12-year-old girl was also in the back seat.
Their identities have not been released.
School district officials say nothing can really help prepare the students for dealing with issues like this.
"There's a great deal of grieving, and it's a time of sadness, particularly when the people who are lost are youngsters, people who have not had an opportunity to really experience life," said school district spokesman John Armato. "It's harder for all of their friends to deal with because, in many cases, this is the first time they're dealing with a serious loss."
Classmates have set up Facebook pages in their memory.
This is the second time in the past month that two young people from the Upper Pottsgrove area have been killed in a crash. Back on November 23rd, two Pottsgrove High School students, Andrew Case and Mike Cantamaglia, were killed.