Four fire engines and 21 firefighters and officers were called to a fire at a house with basement in Walnut Tree Walk in Lambeth.
Part of the basement was damaged by fire. Four adults were led to safety by crews wearing breathing apparatus. Three children self evacuated from the property before the arrival of the Brigade.
All seven people were assessed at the scene by London Ambulance Service crews.
The Brigade was called at 1529 and the fire was under control at 1807. Fire crews from Lambeth, Dowgate and Soho fire stations attended the scene.
The cause of the fire is under investigation.