The 30-year-old was walking in Govanhill at about 8am yesterday when he was approached by the youths looking for cigarettes.
After telling them he did not have any, the men followed him and then assaulted him in Kingarth Street.
He suffered a head injury but managed to make his way home before calling police.
He was taken by ambulance to the Victoria Infirmary for treatment and then discharged.
Detective Constable Mark Hendry, said: "We are carrying out extensive inquiries to trace those responsible for this unprovoked attack."
One attacker was about 20, with dark brown hair and was wearing a blue hooded top. He had a scar on his face. Another was about 17/18, with brown hair and a light top.
The third attacker was also about 17/18, with red hair.