Until 2018, Massachusetts prohibited anyone who wasn't a law enforcement officer from having a stun gun—any type of weapon or portable device that uses an electrical current to incapacitate someone temporarily. After that total ban was struck down as unconstitutional, the state changed its laws to include stun guns in the legal definition of a firearm. That means that Massachusetts residents who want stun guns must meet the state's licensing and other requirements for gun possession and use.
Massachusetts law treats all types of stun guns alike, whether they deliver an electric shock on direct contact or shoot darts attached to wires that carry an electrical charge (like Tasers, a brand name commonly used for this kind of pistol-type device). Previously, the state limited the use of stun guns to law enforcement officers. In 2018, however, the state's highest court found that the absolute ban on civilian possession of these weapons, even in one's own home, violated the Second Amendment's right to keep and bear arms. (Ramirez v. Commonwealth, 94 N.E.3d 809 (Sup. Jud. Ct. Mass 2018).)
Soon after that decision, Massachusetts amended its laws to get rid of the ban but to require regulations restricting the use of stun guns by anyone without a license. Civilians in the state may buy and carry a stun gun if they have license to carry firearms, as long as the electronic device is in a shape that resembles a gun. That explicitly rules out "covert" electronic weapons that resemble other objects like pens. (Mass. Gen. Laws ch. 140, §§ 121, 131, 131J (2019).)
As with other types of firearms, Massachusetts law prohibits certain people from getting licenses for stun guns, including those who:
Because of these restrictions, you'll have to undergo a background check before getting a license for a stun gun. If you're served with an ERPO, you must also surrender your license, along with any stun gun in your possession or control" (Mass. Gen. Laws ch. 140, §§ 131, 131s (2019).)
Although we update this information regularly, states can change their laws at any time. So it's always a good idea to check the current Massachusetts statutes by using this search tool.
Also in response to the Ramirez decision, Massachusetts added a law that requires storing any stun gun in a locked container that can only be opened by the owner or someone else who's legally authorized to use the weapon (Mass. Gen. Laws ch. 140, § 131L (2019)).
It's illegal to enter to or try to enter a secure area of an airport or plane cabin with a stun gun, even if you have a firearms license (Mass. Gen. Laws ch. 269, § 12F (2019)).
If you're facing criminal charges for stun gun violations, including licensing and storage requirements, you should speak to a criminal defense lawyer as soon as possible.