Six fire engines and around 40 firefighters tackled a house fire on Errington Road in West Kilburn.
Part of the lower ground floor of a three-storey mid terraced house was damaged by the fire. There were no reports of injuries.
The fire is being treated as accidental and is believed to have been caused by the unsafe disposal of smoking materials.
A London Fire Brigade spokesperson said: “We’d rather you didn’t smoke at all, but if you are a smoker, it’s absolutely vital you ensure your cigarette is completely out when you’ve finished smoking it.
“If you don’t, you risk causing a fire which could not only destroy your home, but also cost you your life.”
“This incident is timely reminder about the importance of having smoke alarms in your home. Not having working smoke alarms leaves you and your loved ones at risk.
The Brigade was called at 1112 and the fire was under control at 1210. Fire crews from Paddington, Kensington, Willesden, Soho and Hammersmith fire stations attended the scene.
A London Fire Brigade spokesperson said: “Firefighters recommend that you have a look at our online Home Fire Safety Checker to make sure there are no hidden hazards in your home.
“The online tool will ask you a series of questions that will help us work out the level of risk in your home, or the home of someone you care for. It only takes a few minutes to get tailored advice to keep yourself and loved ones safe from fire.”