Police were called to a residential address in Lena Gardens at around 6pm last night.
Officers responded with the London Ambulance Service and found two men with stab wounds.
Despite the efforts of first responders, one of the men, aged 18, died at the scene. His next-of-kin have been informed and are being supported by specialist officers.
The second injured man, aged in his 30s, was taken to hospital where he was later arrested on suspicion of murder.
He remains in hospital in a stable condition and once discharged will be taken into police custody.
It is believed the suspect and victim were known to each other, and police are treating this as an isolated incident.
Superintendent Pali Grewal, who leads neighbourhood policing in Hammersmith and Fulham, said: “Our thoughts remain with the victim’s loved ones as they come to terms with the tragic events of Sunday evening.
“We understand this will be distressing news for those living locally. A crime scene remains in place at Lena Gardens and residents can expect to see increased police patrols in the area. I encourage anyone to approach our officers if you have any concerns or questions.”
Anybody with information that may help police is urged to call 101, quoting reference 5093/15MAR. Alternatively, an anonymous report can be made via independent charity Crimestoppers on 0800 555 111.
