Four fire engines and around 25 firefighters dealt with a flat fire on Whytecliffe Road South in Purley.
Part of a second floor flat was damaged by the blaze. A man left the property, uninjured, before the Brigade arrived. Around 100 residents self evacuated from the building.
The fire is believed to have been accidental and caused by a tea light candle left unattended.
A London Fire Brigade spokesperson said: "Candles, incense sticks and oil burners are one of the most common causes of fire. We’d recommend swapping traditional candles for safer flameless LED alternatives, but if you do use real candles, it’s so important to never leave them unattended.
“Always make sure that they’re held firmly in heat-resistant holders and placed on a stable surface where they won’t be knocked over.”
The Brigade was called by 0347 and the fire was under control by 0429. Fire crews from Purley, Croydon and Wallington fire stations were at the scene.