The incident happened around 8am today (June 11), and police remain at the scene.
The bridge is currently closed to northbound traffic, and City of London Police are urging people to avoid the area.
The woman was treated for a leg injury and taken to hospital by the London Ambulance Service.
Investigations into the incident are ongoing.
Chief Inspector James Minney, City of London Police, said: “City of London Police officers are attending the scene of a road traffic collision involving a bus and a cyclist at 8am on London Bridge.
“The bridge is currently closed to northbound traffic and we’d ask people to avoid the area.
“A woman was taken to hospital by London Ambulance Service.
“Investigations are ongoing.”
A London Ambulance Service spokesperson said: “We were called at 8.29am today (11 June) to reports of a road traffic collision on London Bridge, SE1.
“We sent an ambulance crew, an incident response officer and a clinical team manager to the scene.
“Our first paramedics arrived on scene in approximately five minutes.
“We treated a woman for a leg injury and took her to a major trauma centre as a priority.”
