Six fire engines and around 40 firefighters tackled a fire at a shop on Sidcup Road in Eltham.
The shop on the ground floor of a three-storey building was damaged by the fire. There were no reports of any injuries.
Station Commander Chris Brown, who was at the scene, said: "Firefighters worked incredibly hard in very hot and challenging conditions to bring the blaze under control.
"Fortunately, they were able to contain the damage to the affected area."
The Brigade was called at 1424 and the fire was under control by 1517. Fire crews from East Greenwich, West Norwood, Shadwell and Orpington fire stations were at the scene.
The cause of the fire is under investigation.