Four fire engines and around 25 firefighters were called to a fire at a house converted into flats on Tanfield Avenue in Dollis Hill.
Part of a first floor flat in the two storey semi-detached house was damaged by fire.
One person evacuated the flat before the Brigade arrived. No injuries are reported.
The Brigade was called at 2012 and the incident was over by 2052. Fire crews from Willesden, Park Royal, Wembley and Hendon fire stations were in attendance.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.