One appliance and crew from Thame, one from Beaconsfield and one from Aylesbury attended, along with an officer.
Four people were out of the cars when they arrived.
The firefighters used hydraulic rescue equipment to release one 12-year-old boy, who was passed into the care of South Central Ambulance Service.
The firefighters assisted South Central Ambulance Service in providing immediate emergency care.
Thames Valley Police also attended, and the road was closed while the emergency services worked at the scene.
