Police were called at approximately 3.55pm on Thursday, 5 August to reports of a stabbing on Rowdell Road in Northolt.
Officers attended along with colleagues from the London Ambulance Service and found two victims, including one with stab injuries.
The first man – aged in his 20s – was taken to a west London hospital to be treated for slash injuries to his head. His injuries are not believed to be life-threatening.
The second man – aged in his teens – did not require hospital treatment.
A crime scene was established but has now been closed.
At this early stage, no arrests have been made. Enquiries into the circumstances continue.
Anyone with information relating to this offence is asked to contact the police on 101 or Tweet @MetCC quoting CAD 4354/05AUG.
To remain 100% anonymous contact the independent charity Crimestoppers on 0800 555 111 or visit Crimestoppers_uk.org.