Officers were called to the road outside Bond Street station around 6.45pm yesterday (May 31).
The woman was treated at the scene before being taken to hospital.
Her condition is not yet known.
An air ambulance also landed nearby, drawing the attention of many onlookers in the busy shopping area.
There have been no arrests but police enquiries into the incident are ongoing.
A Met Police spokesperson said: “On Saturday, 31 May police were called to Bond Street, at 18:44hrs following reports of a road traffic collision between a bus and pedestrian.
“Met officers attended the scene alongside paramedics who treated a woman on scene before taking her to hospital.
“We await an update on the woman’s condition.
“There were no arrests, and enquiries into the circumstances remain on-going.”
A London Ambulance Service spokesperson said: “We were called at 6.42pm (31 May) to reports of a road traffic collision near Bond Street Station, W1C.
“We sent multiple resources to the scene, including a paramedic in a fast response car, an ambulance crew and an incident response officer. We also dispatched London’s Air Ambulance.
“We treated a patient at the scene before taking them to a major trauma centre.”
