Six fire engines and around 40 firefighters were called to a fire at a terraced house converted into flats on Upper Belgrave Street in Knightsbridge.
Part of a five-roomed flat on the first floor was damaged by the fire. One woman was led to safety via an internal staircase by crews wearing breathing apparatus. She was treated at the scene for smoke inhalation by London Ambulance Service crews.
The Brigade was called at 2121 and the fire was under control by 2256. Fire crews from Chelsea, Soho, Lambeth and Kensington fire stations were at the scene.
The cause of the fire is under investigation.