Police say the 18-year-old was “set upon” by five people on Stewartstown Road in Twinbrook.
The vicious attack happened around 2.30 am on Saturday, July 23.
He needed surgery on his jaw and also sustained a number of other injuries.
Police in west Belfast have appealed for anyone witnessed the assault or has any information about the attack to contact them on the 101 number.
Alternatively, information can be passed anonymously to Crimestoppers on 0800 555 111.