Emergency services were called to a collision involving a van and car.
It happened at just after 10am on Tuesday on Bierton Road in Aylesbury.
One appliance and crew from Aylesbury attended.
The firefighters provided immediate emergency care to one woman, injured, before passing her into the care of South Central Ambulance Service.
One man was out of the vehicle he had been travelling in, uninjured, before they arrived.
The firefighters assisted Thames Valley Police in making the scene safe.