Four fire engines and around 25 firefighters were called to a fire at a shop with flats above on Station Road in Harrow.
Part of a first floor flat above a shop was damaged by the blaze.
The Brigade was called at 1327 and the fire was under control by 1433. Fire crews from Stanmore, Southall, Harrow and Wembley fire stations attended the incident.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police.