Police and ambulance crews were called to Castle Meadow following the incident that happened at around 6pm.
A spokesman for the East of England Ambulance Service said: “An ambulance, an ambulance officer vehicle and a critical care paramedic car were sent to the scene.
The incident involved a bus. (Image: Newsquest)
“The pedestrian, a teenage girl, was transported to the Norfolk and Norwich University Hospital for further assessment and treatment.”
According to an eyewitness, several buses were queuing in both directions, and the road was blocked.
Other buses were diverted to different routes in the city but services returned to normal after about an hour.
Norfolk Constabulary have been contacted.