Scotland Yard said officers were called to reports of a fight on Gowan Avenue, Fulham, at 12.27am on Saturday.
He was tended to by members of the public before paramedics and police arrived, but was pronounced dead at the scene just before 1am.
Man dies after stabbing in southwest London
The Met said officers were working to inform the mans next of kin and that the Homicide and Major Crime Command had been notified.
Fulham stabbing: Man, 29, dies after fight on same road Jill Dando was killed on
Police were called to reports of a fight on Gowan Avenue in Fulham, west London, early on Saturday morning