Four fire engines and around 25 firefighters were called to a flat fire on Burnley Road in Dollis Hill.
A two-roomed flat on the second floor of a converted terraced house was destroyed by fire. There were no reports of any injuries.
The Brigade was called at 1142 and the fire was under control by 1208. Fire crews from Willesden, Park Royal, West Hampstead and North Kensington fire stations attended the scene.
The cause of the fire is under investigation.