The boy died when the car he was driving collided with a truck on the N21 on the outskirts of Adare at around 2 o'clock this morning.
He was pronounced dead at the scene and has been removed to the morgue at University Hospital Limerick.
Gardai are appealing for witnesses.
Local TD and Junior Minister Niall Collins says it is a terrible tragedy:
"Our thoughts are with the family of the bereaved child, but also of the truck driver who was involved in the accident also, who I know is quite shaken by the events. It's a really shocking incident. We're used to hearing of road collisions but never are we used to hearing of collisions where a child aged 12 was the driver of the vehicle."
