The incident happened in Haven Green just before 5.40pm yesterday (September 17).
Officers were called to the scene and found a man with suspected stab injuries.
He was taken to a west London hospital where his injuries were assessed as not life-threatening.
Another male was arrested on suspicion of GBH at the scene.
He remains in police custody.
Police enquiries into the circumstances are ongoing.
A spokesperson for Metropolitan Police said: “On Sunday September 17 at about 5.38am, police were called to Haven Green, Ealing to reports of a fight.
“Officers attended and found a male suffering with suspected stab injuries.
“He was taken to a West London hospital where his injuries were assessed as not life changing or life threatening.
“Another male was arrested on suspicion of GBH at the scene. He remains in custody.