Three fire engines and around 15 firefighters were called to a maisonette fire on Dorrien Walk in Streatham Hill.
Part of a three-roomed maisonette on the ground floor of the building was damaged by fire. Firefighters wearing breathing apparatus assisted a woman from the property. There were no reports of any injuries.
The Brigade was called at 1506 and the fire was under control by 1533. Fire crews from Brixton, Norbury and Clapham fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.