Four fire engines and around 25 firefighters attended a fire at a house converted into flats in Hortus Road, Southall.
Part of the first floor flat was damaged by fire. Five people left the property before the Brigade arrived.
The Brigade was called at 0556 and the fire was under control by 0708.
Fire crews from Southall, Ealing, Hayes and Heston stations attended the incident
The cause of the fire is under investigation.