Three teenagers were headbutted, punched and kicked during an unprovoked attack in the Xscape last week.
The incident happened between 4.05am and 4.15am on Friday, September 26, when the three teenagers were assaulted by two other men in their late teens/early twenties.
Police are keen for the victims to get in touch.
The incident began between the Wonderworld club and Harvester pub, before moving to the outside entrance of McDonald’s and towards the casino.
The victims were headbutted, punched and in one case kicked by the offenders, but did not retaliate before they managed to get away.
PC Katie Smith said: “This was a particularly nasty assault on three men who did nothing to provoke the offenders.
“We have never spoken to the victims but would like to make contact with them to reassure them that we are investigating this case.
“Thames Valley Police takes violent assaults seriously and we want to reassure the victims, and wider public in general, that such behaviour will not be tolerated.”
If you were one of the victims call Thames Valley Police on 101 or call Crimestoppers, anonymously, on 0800 555111.