The incident happened in Creukhorne Road, near Church Road just before 7pm yesterday (January 28).
Officers and London Ambulance Service crews attended and found a man who had been shot.
He was taken to hospital where his condition is unknown at this stage.
A cordon remains in place with the road closed by police tape and officers at the scene.
A London Ambulance Service spokesperson said: “We were called at 6.53pm on Wednesday 28 January to reports of a shooting on Creukhorne Road, NW10.
“We sent resources to the scene including an ambulance crew, an advanced paramedic, a paramedic in a fast response car and an incident response officer.
“We also dispatched a trauma team in a car from London’s Air Ambulance.
“We treated a man for a gunshot wound and took him to a major trauma centre.”