Four fire engines and 21 firefighters and officers were called to a fire at a house in Ealing Road in Wembley.
Part of the ground floor of the property was damaged by fire.
Three adults and two children left the property before the arrival of the Brigade. There were no reports of any injuries.
The Brigade was called at 2003 and the fire was under control at 2126. Fire crews from Park Royal, Northolt, Acton and Ealing fire stations attended the scene.
The cause of the fire is under investigation.