Four fire engines and around 25 firefighters tackled a fire involving a range of commercial units on High Street Harlington.
Most of the single-storey units were damaged by fire. There were no reports of any injuries.
The Brigade was called at 0345 and the fire was under control by 0503. Fire crews from Heathrow, Hayes and Feltham fire stations attended the scene.
The cause of the fire is under investigation.