Four fire engines and around 25 firefighters were called to a flat fire on Westcote Road in Streatham.
Most of a three-roomed flat on the first floor of a converted end-of-terrace house was damaged by fire. Two women were treated on scene by London Ambulance Service crews.
The Brigade’s 999 Control Officers took 11 calls to the blaze.
The cause of the fire is believed to have involved a candle.
A London Fire Brigade spokesperson said: "Candles are one of the most common causes of fires in the home. It’s important that you never leave them unattended and keep them away from anything that could catch fire such as curtains, furniture or clothes.
"We’d recommend swapping traditional candles for safer flameless LED alternatives, but if you do use real candles, 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 at 1547 and the fire was under control by 1702. Fire crews from Norbury, West Norwood, Brixton and Woodside fire stations attended the scene.