Two fire engines were called to a blaze at a block of flats in Sparks Close, Acton.
Part of a flat on the second floor of the building was damaged by fire.
One woman was led to safety by crews wearing breathing apparatus and she was treated at the scene for smoke inhalation by London Ambulance Service.
The Brigade was called at 1451 and the fire was under control at 1527. Fire crews from Acton and Park Royal fire stations attended the scene.
The cause of the fire is under investigation.