Four fire engines and around 25 firefighters were called to a fire at a house in Tenterden Drive in Hendon.
Part of a first floor bedroom of the semi-detached house was damaged by the fire. One woman was rescued by crews wearing breathing apparatus. She was taken to hospital by London Ambulance Service crews.
The Brigade was called at 0500 and the fire was under control at 0531. Fire crews from Hendon and Finchley fire stations attended the scene.
The cause of the fire is under investigation.