Emergency services were called to Botley Road at around 2:30pm.
Police say they received reports of a collision involving a bus and a cyclist near the McDonald's restaurant (09/05)
It has been confirmed that a 31-year-old female cyclist was sadly pronounced dead at the scene. Her next of kin have been informed.
The Oxford Bus Company vehicle was operating the 4B service towards the city and Wood Farm.
Managing Director, Phil Southall, said: "It is far too early to speculate as to the cause of the incident and we are doing everything we can to assist the emergency services at this time.
"Our thoughts are with the friends and family of the cyclist and our driver who is currently receiving treatment for shock."
Investigating Officers are now appealing for information.
Police Staff Investigator Julie Hunt of the Serious Collision Investigation Unit, based at Bicester police station, said: "I would like to hear from anyone who was in the area at the time of this incident, who witnessed it, or who has any information that could help with our investigation.
"If you have any information please contact me via the Thames Valley Police non-emergency number 101."
Motorists were advised to avoid the area yesterday - the Botley Road has since reopened.
Due to an incident on Botley Rd, our 4, U1 and 400 services are diverting away from the incident.— Oxford Bus Company (@OxfordBusCo) May 9, 2017