Two fire engines and around 10 firefighters were called to a fire at a flat on Devonshire Road in Hatch End.
Part of a flat roof of the three-storey building was damaged by fire. Two men were led to safety by firefighters using a ladder. There were no reported injuries.
The Brigade was called at 1656 and the fire was under control by 1743. Fire crews from Harrow and Northolt fire stations attended the scene.
The cause of the fire is under investigation