The shooting happened at about 8.50 pm at Forest Street, off the Springfield Road.
A PSNI Crime Scene Investigation team spent the night combing the area for clues to the gunman.
The youth was rushed to the nearby Royal Victoria Hospital for treatment in the accident and emergency department.
He is said to be in a stable condition following surgery.
The gun attack came just 24 hours after a man was shot in the legs on Wednesday night in west Belfast.
The shooting happened close to the jobs and benefits office on the Falls Road.
He is also said to be in a stable condition.
Sinn Féin’s Fra McCann has condemned the shooting.
“The shooting in Forest Street in west Belfast was wrong and I condemn it.
“There can be no justification for such actions and whoever is responsible needs to stop.
“I would encourage anyone with information to bring it forward to the PSNI.”