The incident happened on Saturday 13 September at around 1.20am near to the Buttercross in Witney town centre.
The victim was assaulted outside the Angel Inn Public House and was punched to the face repeatedly.
He was then assaulted shortly after this as he was followed across the road.
Investigating officer PC Liam Dunkley based at Witney police station, said: “We would like to speak to anyone with information about this incident.
“In particular we would like to speak to the victim in this attack who has not come forward to the police at this point.
“If you think you saw anything or have details about what happened, please get in contact.
“You can do so by contacting the Thames Valley Police non-emergency number 101 or by making a report online using the reference number 43200286796.
“If you would prefer to remain anonymous you can contact the independent charity Crimestoppers by calling 0800 555 111.”
Notes to editors:
Two men aged 19 and 20 from Eynsham have been arrested on suspicion of affray and have since been released under investigation.