The woman was physically assaulted in the early hours of Saturday, 28 September and has since been discharged from hospital.
Officers were called to Hampton Court Road at 04:20hrs by colleagues from the London Ambulance Service, who were treating the victim.
It is believed the woman, who is in her 20s, was assaulted in the area of Hampton Court Road, near to Kingston Bridge. It is thought to have happened on the grass verge on the left side of the road, heading towards Hampton Court from Kingston.
PC James Driver, said: “This assault left the victim unconscious and we would like to speak to anyone who thinks they may have seen what happened.
“There were a number of people returning home from a night out in the High Street around the same time, and I think there might have been some witnesses who saw something which could assist our investigation.
“We are also very keen to ask people to check their dash-cam footage.
“Please come forward to police in Kingston directly, or make the call anonymously – either way, you could really help our enquiries.”
Anyone with information is asked to contact police via 101 or tweet @MetCC quoting reference Cad 1367/28Sep or call Crimestoppers 100% anonymously on 0800 555 111.
A man has been arrested and charged in connection with this incident