Deputies with the same agency responded to the 31000 block of Dunham Lake Drive in Hockley around 6:30 p.m.
One parent was home with the boy, but it's not clear where the gun was being kept, a sheriff's spokesman said.
It's also not clear whether it was a privately owned weapon or a service firearm used in the shooting
The boy's current condition is not known, but he was air lifted to the medical center around 7:00 p.m.