Four fire engines and around 20 firefighters and officers were called to a fire in Croydon Road in Beckenham in the early hours of Saturday morning.
A large quantity of rubbish in a rear garden was damaged by fire.
Two people were rescued via a ladder from a first floor flat. Nine other people left the building before the arrival of the Brigade. One woman and one man were treated at the scene for smoke inhalation by London Ambulance Service crews.
The Brigade was called at 0055 and the fire was under control at 0233. Fire crews from Beckenham, Woodside and Bromley fire stations attended the scene.
The cause of the fire is under investigation.