Four fire engines and around 25 firefighters were called to a flat fire on London Road in Kingston.
A flat on the third floor of a four-storey block was damaged by the fire. A man, a woman and two children left the property before the Brigade arrived. They were treated at the scene for smoke inhalation by London Ambulance Service crews.
The cause of the fire is believed to be accidental and involved a candle.
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 at 1855 and the fire was under control by 2035. Fire crews from Surbiton, Kingston, New Malden and Twickenham fire stations were at the scene.
Firefighters' candle safety top tips