The attack was reported at about 10 p.m. Tuesday outside a bar in the 5700 block of Mission Street.
The 31-year-old victim was pulled outside of the bar by five suspects who apparently did not like his shirt, according to police.
The suspects beat the man and also took his cellphone and cash before fleeing, police said.
The victim suffered a cracked tooth and a contusion to his hip during the attack. He was able to drive himself to a hospital to be treated for his injuries, which are not life-threatening, according to police.
The suspects have not been found as of this morning. Anyone with information about the case is encouraged to call the Police Department's anonymous tip line at (415) 575-4444 or send a tip by text message to TIP411.