The men had attended a celebration at the Celtic Supporters Club on Glasgow's London Road and had gone outside to look for a taxi when they were assaulted by a group of about 15 people in the early hours of Sunday.
The men - aged 23, 24, 25 and 27 - were treated at Glasgow Royal Infirmary before being released.
Police are appealing for information on members of the gang, who are believed to live locally.
They were white, aged between 20 to 25 and were wearing tracksuits
Detective Constable Edwina Perry said: "This was a unprovoked attack on a group of men on a night-out. It's clear these youths were intent on causing trouble.
"I am appealing to local people who may have some knowledge about these youths to get in touch with us.
"We know that a lot of people were at the engagement party at the club and guests were ordering taxis to get home.
"I would like to appeal to any taxi drivers who were in the area and who may have seen something or who may have seen these youths, perhaps earlier in the night, to please call us."
Anyone with information is asked to contact police on 101.