Five fire engines and around 35 firefighters were called to a flat fire on Edenham Way, North Kensington.
Around half of a fourth floor flat was damaged by fire. One woman left the property before the Brigade arrived. She was suffering from smoke inhalation and taken to hospital by London Ambulance Service crews.
The Brigade was called at 2328 and the fire was under control at 0035. Fire crews from North Kensington, Paddington, and Kensington fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.