Four fire engines and around 25 firefighters were called to a fire at a block of flats in Baywillow Avenue in Carshalton.
Part of a maisonette on the ground and first floors was damaged by fire. One woman left the property before the arrival of the Brigade.
The Brigade was called at 1402 and the fire was under control at 1452. Fire crews from Wallington, Norbury, Sutton and Tooting fire stations attended the scene.
The cause of the fire is under investigation.