Six fire engines and around 40 firefighters were called to a gas leak on Malvern Road in West Kilburn.
A 24-inch gas main ruptured. Crews also discovered a nearby burst water main which caused a sink hole measuring around 4 metres in diameter and 4 metres deep. Around 50 properties were evacuated and a 25-metre cordon was put in place. Around 120 people were moved to a local rest centre. There were no reports of any injuries.
Station Commander Tom Sharp, who was at the scene, said: "Crews worked closely with emergency services to carry out evacuations of the local area. There was a strong smell of gas and we encouraged people to keep their windows and doors closed.
"Multi-agency service partners are continuing to work to make the scene safe and will be on scene through the night."
The Brigade was called at 1650 and the incident was over for firefighters by 0418. Fire crews from Paddington, North Kensington, Kensington, Hammersmith and surrounding fire stations attended the scene.