A 15-year-old girl was rushed to hospital following the incident in Abbots Drive, off Rayners Lane , on Saturday (February 10) evening.
She was treated for "non life threatening" injuries.
The Metropolitan Police said on Wednesday (February 14) that "no arrests" have been made.
It said police enquiries are ongoing and the victim has been discharged from hospital.
Officers from Harrow CID continue their investigation into the stabbing and are keeping "an open mind as to motive at this time".
Just 48 hours later a man was fighting for his life after being stabbed outside Harrow-on-the-Hill station in College Road.
This makes it the fifth stabbing in Harrow getwestlondon has reported in since the new year.
On January 2, a man was chased and stabbed at least 10 times outside his doorstep in Eastway Crescent, a few roads away from Saturday's stabbing.
A 17-year-old was slashed outside the Zoroastrian Centre in Alexander Avenue on January 22, just a few hundred metres from Abbots Drive.
Later that week, on January 26, another man was stabbed in Roxborough Park , near Harrow-on-the-Hill station.
Anyone who witnessed this incident or has information is asked to contact Harrow Police on 101, tweet @MetCC or call Crimestoppers anonymously on 0800 555 111.
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