The accident happened Saturday afternoon in his front yard.
According to Charles County, Maryland, authorities the four-wheeler is designed to be operated for children 6-12 years of age.
The boy's mother turned the ATV off using the vehicle's remote cut-off switch. At that moment, the ATV came to a stop, but the front wheels turned causing it to topple onto the boy.
The boy, whose name has not been released, was flown to Children's National Medical Center in Washington, D.C. where he was pronounced dead. The boy was wearing a helmet.
The accident remains under investigation.