Four fire engines and 21 firefighters and officers were called to a fire at a house in Grosvenor Road in Edmonton.
The ground floor of the terraced house was destroyed by fire.
Three adults and three children left the property before the arrival of the Brigade. A further three adults and three children left a neighbouring property before firefighters arrived.
The Brigade was called at 0411 and the fire was under control at 0532. Fire crews from Edmonton and Enfield fire stations attended the scene.
The cause of the fire is under investigation.