Automatic knives are legal to carry in Massachusetts. In 2024, the Massachusetts Supreme Judicial Court struck down the state’s longstanding switchblade ban, holding that it violated the Second Amendment. You can now carry an automatic knife openly or concealed under state law, with no blade-length cap, age threshold, or permit requirement — but school zones, certain local ordinances, and federal shipping rules still apply.
What the 2024 Ruling Changed
For decades, Massachusetts General Laws Chapter 269, Section 10(b) made it a crime to carry a switchblade or any knife with an automatic spring-release mechanism and a blade longer than one and a half inches.1General Court of Massachusetts. Massachusetts General Laws Chapter 269 Section 10 In Commonwealth v. Canjura, the Supreme Judicial Court held that prohibition unconstitutional and reversed the defendant’s conviction.2Justia Law. Commonwealth v. Canjura
Carrying an automatic knife is no longer a crime under Section 10(b).3Mass.gov. Massachusetts Law About Weapons (Non-Firearms) The switchblade language still sits in the statute’s text because the legislature has not amended it, but that portion is unenforceable. Massachusetts also draws no distinction between open and concealed knife carry, so how you carry an automatic knife on your person does not change your legal exposure under state law.4Mass.gov. Massachusetts General Laws c.269 Section 10 – Carrying Dangerous Weapons
Where You Still Cannot Carry One
Section 10(j) makes it a crime to possess a firearm or any “other dangerous weapon” in any elementary school, secondary school, college, or university, including the grounds and school transportation, without written authorization from the school board or officer in charge.5General Court of Massachusetts. Massachusetts General Laws Chapter 269 Section 10 An automatic knife can qualify. The penalty is a fine of up to $1,000, up to two years in jail, or both. The exemptions are narrow: qualified active and retired law enforcement officers under the federal Law Enforcement Officers Safety Act, and certified Massachusetts law enforcement officers under Chapter 6E.
Massachusetts has no statewide knife preemption law, so cities and towns can set their own rules, and those rules can be stricter than state law. Before carrying an automatic knife in a particular city or town, check whether a local ordinance applies. Legal under state law does not always mean legal on your block.
Buying and Shipping One
The Federal Switchblade Act, 15 U.S.C. §§ 1241–1244, restricts shipping and selling automatic knives across state lines. Knowingly shipping, transporting, or distributing a switchblade in interstate commerce carries penalties of up to $2,000, up to five years in prison, or both.6GovInfo. U.S. Code Title 15 Chapter 29 – Manufacture, Transportation, or Distribution of Switchblade Knives
The federal definition covers any knife with a blade that opens automatically by pressing a button or other handle device, or by gravity or inertia. Common carriers transporting knives in the ordinary course of business are not liable. In practice, many retailers ship automatic knives to states where possession is legal, and the federal law is rarely enforced against individual buyers; the legal risk falls primarily on commercial sellers and distributors.
Knives That Are Still Illegal to Carry
Canjura addressed switchblades only. Section 10(b) still bans carrying several other knife types, and those restrictions remain in force:1General Court of Massachusetts. Massachusetts General Laws Chapter 269 Section 10
- Stilettos and daggers
- Dirk knives
- Double-edged knives
- Ballistic knives (knives with a detachable blade propelled by a mechanism)
- Locking-blade knives housed in a device or case that lets the blade be drawn in a locked position
Standard folding knives, fixed-blade hunting knives, and kitchen knives are not on the Section 10(b) list and are generally legal to carry. Whether any of the still-banned categories could survive a Second Amendment challenge like Canjura’s is an open question, but until a court rules otherwise, carrying one of them remains a crime.
Automatic vs. Assisted-Opening Knives
If you are shopping and see “assisted opening” or “spring-assisted,” those are not automatic knives. An assisted-opening knife has a spring that helps the blade deploy, but you must first apply manual pressure to the blade itself to overcome the spring’s bias toward staying closed. An automatic knife deploys the blade entirely by a button or switch on the handle, with no contact on the blade.
Assisted-opening knives were never covered by the Massachusetts switchblade ban, and the Federal Switchblade Act explicitly exempts them.6GovInfo. U.S. Code Title 15 Chapter 29 – Manufacture, Transportation, or Distribution of Switchblade Knives They face no special restrictions under either Massachusetts or federal law.