Four fire engines and 21 firefighters and officers were called to a fire at a restaurant with flats above in Queensway, Bayswater.
Part of the ground floor, first floor and staircase of the building were damaged by fire.
The restaurant's extraction system from the ground to fourth floor was also damaged.
Eight people left the building before the arrival of the Brigade and there were no reports of any injuries.
The Brigade was called at 0131 and the fire was under control at 0437. Fire crews from Kensington, Paddington and Hammersmith fire stations attended.
The cause of the fire is believed to have been due to a build up of grease in the ducting.
A London Fire Brigade spokesperson said: “Restaurant and take-away owners should always take care to make sure their extraction systems are kept clean as a build up of fat and grease within the filters can lead to a fire.”