Around 100 firefighters were called to a fire at a warehouse of two floors on an industrial estate on Barretts Green road, Willesden.
Around half of the ground and first floor were damaged by fire. The blaze also affected the roof.
Fifteen fire engines and three aerial appliances from Park Royal, Acton, Willesden, Wembley, North Kensington, West Hampstead, Ealing, Chiswick, and Hammersmith fire stations attended the incident.
Station Manager Garry Brown, who was at the scene, said:
"The fire made its way through to the roof of the warehouse and caused a lot of smoke so we advised those living nearby to keep windows and doors shut."
Firefighters will remain at the scene throughout the morning damping down small pockets of fire.
The Brigade was called at 2125 and the fire was under control at 0454.
The cause of the fire is under investigation.