Police were called to Camomile Way in Yiewsley North west London at around 1500 hours following reports of a stabbing.
The incident took place as parents collected children from a nearby school.
Metropolitan police officers attended along with the London ambulance service and found a male with stab wounds.
The males injuries are not thought to be life threatening at this stage.
An Air Ambulance was seen circling and landed nearby.
Multiple witness accounts state a firearm was discharged during the incident, however, the police are yet to confirm this.
The victim was taken to hospital by air ambulance.
Police remain on scene and a cordon is in place. Three arrests have been made in relation to the incident.
Traffic is slow along Falling Lane and the surrounding areas as investigations take place.