Thames Valley Police is appealing for witnesses or information following an incident of assault occasioning actual bodily harm.
At around 11.15pm on Saturday, a 31 year-old man was assaulted by several people in The Plough pub on London Road, Stony Stratford.
The victim was punched to the face and hit on the head with an object, believed to be a glass.
He sustained injuries to his head and mouth which required hospital treatment. He has since been discharged.
One of the offenders is described as a white man, who had a ponytail and was wearing a chequered shirt.
Investigating officers would like to speak to anyone who witnessed the incident.
If you have any information which may assist with the investigation, please call PC Rebecca Wade on 101, quoting incident reference 43170131116 or contact Crimestoppers anonymously.