Four fire engines and around 25 firefighters tackled a flat fire on Craven Park Road in Harlesden.
A first-floor flat, situated above a shop in a mid-terraced building, was destroyed by fire. One person at the scene was taken to hospital suffering from smoke inhalation.
The Brigade was called at 0810 and the fire was under control by 1036. Fire crews from Willesden, North Kensington, Acton and Wembley fire stations attended the scene.
The fire is believed to have been caused by an electrical fault.