Police were called to reports of a disturbance in Jubilee Road, Perivale at 1.40am today (February 28).
London Ambulance Service crews also attended, however, the woman died at the scene.
A 49-year-old man, believed to be known to the victim, was arrested at the scene on suspicion of murder.
He remains in police custody at a west London station.
The cause of death is currently unknown and a post-mortem is due to take place.
A cordon is expected to remain at the scene while officers collect evidence.
The woman’s family has been made aware and is being supported by specially trained police officers.
Detective Superintendent Rebecca Reeves, who leads policing in Ealing, said: “I am deeply saddened by this incident, and I know residents in our local area will be too.
“We have a suspect in our custody and although our investigation is in its early stages, we believe this man was known to the victim.
“We have secured a scene and this will be in place for the remainder of the day, so our officers can obtain crucial evidence for their investigation.
“Our neighbourhood officers will also be present in the area throughout the day – if any local residents have concerns please speak to them. We are there not only to support our investigation team but also there to support you as a community.
“If you know anything that may help us, then please come forward to police by calling 101 stating CAD438/28FEB.”
