It happened in the Glenkeen area of Poleglass on Thursday at around 8 pm.
The 18-year-old was approached by two men who walked him along a pathway and forced him to lie down on the ground, before shooting him once in each leg.
The man was later taken to hospital for treatment. His injuries are not believed to be life-threatening.
Lisburn police have appealed for witnesses, and said they wanted to speak to a man of heavy build who got into a red saloon car after the shooting.