The boy was struck by a van on Slavery Road, Buncrana at approximately 5.30pm.
The road remains closed.
“Gardaí in Buncrana are appealing for witnesses following a collision involving a pedestrian and a van,” a Garda spokesperson said.
The boy was treated at the scene by emergency services personnel.
Due to the extent of his injuries, the schoolboy was removed by ambulance and rushed to Altnagelvin Hospital.
His condition is understood to be serious.
The driver of the van, a man in his 50s, was uninjured.
The Garda spokesperson said: “The scene is preserved for examination by Garda Forensic Collison Investigators and local diversions remain in place.
“Gardaí are appealing to anyone who may have information regarding the collision, particularly any road users with camera footage who were travelling on the Slavery Road between 5.15pm and 5.45pm on 21st February 2020, to contact Buncrana Garda Station on 074 932 0540, the Garda Confidential Line on 1800 666 111 or any Garda Station.”