The victim has been identified as Juan Carlos Robles-Corona of the 2200 block of North 15th Street.
The shooting happened at about 2:40 p.m. Monday on the same block, near Dr. Tanner G. Duckrey Public School.
Robles-Corona, who was in the 8th grade, was shot four times while walking home along 15th Street.
"These people come up southbound to get him. Not sure if there's one or two shooters, but there were 20 shots fired," said Captain John Walker with the Philadelphia Police Department.
Officers heard the gunshots and raced over. They rushed the teen to an area hospital where he died from his injuries.
A backpack, a math textbook and a notebook were left behind at the crime scene.
Robles-Corona had left school about a half-hour early and was gunned down near his front door about 10 minutes later.
"How much hatred could they have had on my son to have shot him the way they shot him? 20 shots," said his mother, Maria Balbuna.
"I believe that something happened in school that made home upset and he left, and whatever happened in school led to him getting ambushed out here," she said.
The family moved to Philadelphia two years ago with hopes of saving up and buying a house somewhere safer.
Balbuna is unsure why her son left school early, why she wasn't notified, and ultimately why her son's life was senselessly taken.
"As a mother I just need to know what happened. I need this closure for me. We didn't come here for this. We didn't come here for this," Balbuna said. "I need to know why. What did he do? What did he do to be killed like this and left in the street like garbage?"
His family says Robles-Corona was the oldest of four children, a responsible son who looked after his brothers and worked with his mom at Auntie Anne's pretzels on weekends, saving up to buy a vending machine and help out with family bills.
No weapons were recovered and no arrests have been made.
This shooting came just hours before a 13-year-old was shot multiple times while sitting inside a car in West Philadelphia.
Anyone with information is asked to call police at 215-686-TIPS.