Four fire engines and around 25 firefighters were called to a fire at a block of flats on Wolseley Street in Bermondsey.
Half of a flat on the ground floor of a four-storey block was damaged by the fire. There were no reports of any injuries.
The Brigade was called at 1617 and the fire was under control by 1718. Fire crews from Dockhead, Tottenham, Old Kent Road and Deptford fire stations were at the scene.
The Brigade's fire investigators believe the fire was caused by a build up of lint around the heating element in a tumble dryer.