Two men and a woman forced their way into a house in Glasgow's east end last night and assaulted the teenager with a blunt weapon.
A boy aged 13 was also assaulted in the incident on Whitevale Street in Dennistoun just before 10pm.
A 47-year-old woman living at the address was not injured.
Detective Inspector Ogilvy Ross, from Police Scotland, said: "We're continuing significant enquiries into the circumstances of this incident and would like to reassure the public and local community that we believe this attack is not random.
"Our enquiries have revealed that shortly after the incident at Whitevale Street, a Ford Mondeo car was vandalised in Bellfield Street at around 10.05pm.
"I'd like to speak to any local people who may have witnessed anyone acting suspiciously around Bellfield Street around that time to contact us - they may have information which could assist with our enquiries."
The 16-year-old is being treated at Glasgow Royal Infirmary where doctors described his condition as stable.
The younger boy was discharged following treatment for a minor injury to his knee.
Anyone with information is asked to contact Police Scotland on 101 or Crimestoppers on 0800 555 111.