The collision occurred on the B1150 North Walsham Road, between North Walsham and Norwich, at around 8.30am.
Police and fire crews from Sprowston and Earlham attended the scene, using hydraulic rescue equipment to free trapped individuals from their vehicles.
The incident was brought under control by 9.28am, according to the stop message received by emergency services.
Traffic in the area was heavily affected, with the AA Traffic Map showing significant delays at the time.
The extent of injuries remains unclear, and the East of England Ambulance Service has been contacted for further information.
