Four fire engines and 21 firefighters and officers were called to a fire at a house in Ashdale Road, Lee.
Part of the ground floor, first floor and roof of the property were damaged by fire.
The Brigade was called at 0953 and the fire was under control at 1210. Fire crews from Lee Green. Eltham and Bromley fire stations attended the scene.
The cause of the fire is under investigation by the Metropolitan Police Service.
Anyone with information should call Lewisham Police on 101 or Crimestoppers anonymously on 0800 555 111.