He was discovered at 1 am on Saturday, Saturday, December 12 at Glasvey Close in the Twinbrook area.
Security sources said he has sustained a “brutal attack”.
Det Ch Insp Gareth Talbot said: “After examination by ambulance staff the man was pronounced dead at the scene.
“A number of injuries were noted on the body and as such, we are treating this death as murder.”
Police appealed for anyone with information to contact them.
“I would appeal to anyone who has any information or who witnessed any disturbances in the area of the Stewartstown Road or Glasvey Close to contact detectives at Musgrave on 101,” added DCI Talbot.
Sinn Féin MLA Jennifer McCann has said she was shocked to hear that a teenager died last night in what the PSNI are describing as a violent attack.
Ms. McCann said:
“I was shocked to hear that a teenager was found dead in the early hours of this morning in the Twinbrook area.
“I have spoken to the local PSNI and they tell me they are treating it as a violent death.
“My thoughts and prayers are with this young mans family at this time and I would appeal to anyone with information to bring it forward to the PSNI.”