Metropolitan police have rushed to the scene at Sudbury Hill station, Harrow, following the incident.
Some eyewitnesses have claimed to have heard five gunshots outside the Tube station.
Police confirmed the victim is 19-years-old but his condition is unknown.
They confirmed the shooting took place at 6.40pm today.
Met Police spokesman said: “Police were called to Greenford Road, Harrow, at 18:40hrs on Wednesday, 18 November following reports that a man had been shot outside Sudbury Hill Station.
“Officers attended alongside London Ambulance Service.
“A 19-year-old man has been taken to a west London hospital suffering with gunshot wounds.
“His condition is unknown.
“No arrests have been made but officers remain in the area and enquiries continue.
“Greenford Road is closed and trains are not stopping at Sudbury Hill Station.”
The London Ambulance Service treated the man for his gunshot wounds before he was taken to the hospital.
A police cordon was also set up, while the Met have appealed for any witnesses.
More to follow…