Four fire engines and around 25 firefighters were called to a fire at a block of flats on Defence Close in Thamesmead.
Part of a three-roomed flat on the third floor was damaged by fire. One woman was rescued by crews wearing breathing apparatus and was taken to hospital by London Ambulance Service suffering from smoke inhalation. Four people from neighbouring flats were led to safety by crews, via an internal staircase, and around 20 people left the building before the Brigade arrived.
The Brigade was called at 0713 and the incident was over by 0842. Crews from Plumstead and East Greenwich fire stations were at the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.