Police say a man approached the victims on foot outside Our Lady of Peace Catholic School, pulled out a gun and started firing.
Some of the dozen people at the bus stop jumped on to a CTA bus that became a shield.
In all, five people were hit by gunshots.
"They shot one of the girls in the back or the arm or something like that. and the boy I think got shot in the chest or back or something, and somebody else got shot in the leg," said witness Shantilla Moore.
Police say the gunman then fled in this minivan which was recovered, along with a weapon in the 7500 block of Essex.
"At any given time the person being shot could lose his life. Someone always wants to retaliate and the end result being an innocent kid being struck and killed by some foolish mistake," said activist Andrew Holmes.
Another 16-year-old was hit in the chest and is in surgery at Stroger County Hospital.
A 19 year old female hit in the side was taken to NW Memorial and is in critical condition, while a17-year-old male was taken to South Shore Hospital with a graze wound in the stomach.
Later a 20-year-old male with a hand injury walked in to south shore for treatment.
"You have certain individuals that just don't get the message about this gun violence," Holmes said. "Then you also have those on the other hand that can help solve these cases all it take is to pick up the phone."