Four fire engines and around 25 firefighters tackled a fire at a recycling centre on Forward Drive in Harrow.
Around 50 tonnes of rubbish was alight. There were no reports of any injuries.
The Brigade's 999 Control Officers received six calls about the fire.
The Brigade was called at 2230 and the fire was under control by 0030. Crews from Harrow, Stanmore and Northolt fire stations attended the scene.