Six fire engines and around 40 firefighters tackled a fire on Neasden Lane in Neasden.
Most of a shop on the ground floor of a three-storey building was damaged by fire. Seven people were led to safety by firefighters wearing breathing apparatus from a flat on the first floor. There were no reports of any injuries.
The Brigade's 999 Control Officers received seven calls about the fire.
The Brigade was called at 0035 and fire was brought under control by 0227. Crews from Willesden, Park Royal, North Kensington, Wembley and Hendon fire stations attended the scene.
The fire is believed to have been caused by an electrical fault.