Four fire engines and around 25 firefighters were called to a fire at a shop on Upper Tooting Road in Tooting.
Most of the ground floor of a shop was damaged by the fire and there was smoke damage to flats above. There were no reports of any injuries.
The Brigade was called at 0228 and the fire was under control by 0410. Fire crews from Tooting, Wimbledon, Wandsworth and Clapham fire stations were at the scene.
The cause of the fire is under investigation.