She was attacked near to the Moo Moo Clubrooms.
The 20-year-old victim left the club in High Street last night (09/02) and walked into an alleyway.
She was approached from behind by a man who then raped her before leaving the scene.
The offender is described as a white man with a moustache.
The victim is currently being supported by specially trained officers, and a scene watch is in place in Banbury while an investigation into the incident takes place.
Police also say there is likely to be an increased police presence in Banbury town centre today while officers carry out enquiries.
Investigating officer, Detective Inspector Matt Bick, based at Banbury police station, said: “This is clearly a very distressing incident, which I understand will cause concern in the community, but I would like to reassure people that we are carrying out a full and thorough investigation.
“As we are in the early stages of this investigation, we are unable to release further details of the incident at this time, but we will provide updates when it is possible for us to do so.
“I would ask anyone who has any information which they think could relate to the incident, no matter how insignificant it may seem, to contact us.
“If you have any information which you think could help our investigation, please call Thames Valley Police on 101.”