Three fire engines and around 15 firefighters were called to a fire at a house on Windsor Close in West Norwood.
Half of the first floor of a two-storey terraced house was damaged by fire. Firefighters wearing breathing apparatus rescued one woman from the ground floor of the building. She was treated on scene by London Ambulance Service crews. Another woman and two men left the building before the Brigade arrived.
The Brigade was called at 0213 and the fire was under control by 0317. Fire crews from West Norwood and Norbury fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.