Four fire engines and 21 firefighters and officers were called to a fire at a flat in Nicoll Road, Harlesden.
Part of a five-roomed flat on the ground floor was damaged by the fire. There were no reports of any injuries.
The Brigade was called at 1136 and the fire was under control at 1219. Fire crews from Park Royal, Willesden and North Kensington fire stations attended the scene.
The cause of the fire is under investigation.