The Michigan appeals court said the state can't stop people from owning stun guns on Wednesday.
A three-judge panel at the court said the Michigan and U.S. constitutions allow people to bear arms.
The court said a total prohibition on stun guns can't stand.
The decision involved cases from Bay City and Muskegon.
In Bay City, a store employee was carrying a stun gun while he worked behind the counter.
In Muskegon, a stun gun was seized from a man at his home.
A new Michigan law that takes effect in August would allow people to have stun guns if they also have a permit to carry a concealed weapon.
That law was not at issue in the cases at the appeals court.