🎓 Massachusetts Knife Laws
Overview
Massachusetts does not have statewide preemption, so local ordinances may impose additional restrictions. Both open and concealed carry face restrictions. There is no general blade length restriction. Ballistic knives are prohibited; switchblades, disguised knives, and assisted-opening have restrictions.
Quick Legal Facts
Carry Laws & Blade Length
M.G.L. ch. 269 § 10(b) prohibits carrying 'on his person' certain per se dangerous weapons: stilettos, daggers, ballistic knives, dirk knives, knives with double-edged blades, and devices enabling a locking blade to be drawn at a locked position. The statute does not distinguish between open and concealed carry — it simply prohibits carrying on one's person. Automatic knives with blades under 3 inches are now permitted for adults 21+ following Commonwealth v. Canjura (2024) and 2025 legislation. No statewide preemption; Boston limits blades to 2.5 inches.
Statute: 10.
Massachusetts does not create a separate category for concealed carry of knives. M.G.L. ch. 269 § 10(b) prohibits carrying the listed per se dangerous weapons on one's person regardless of method. For legal knife types (ordinary folding pocket knives), both open and concealed carry are generally permitted. For prohibited types, carry is illegal regardless of visibility.
Statute: 10.
No general statewide blade length limit for all knives. The 3-inch threshold applies specifically to automatic knives (switchblades) — adults 21+ may carry automatics with blades under 3 inches following Canjura (2024) and 2025 amendments. § 12 restricts manufacturing/selling automatic knives with blades over 1.5 inches. Boston and surrounding cities limit blades to 2.5 inches by local ordinance. No statewide preemption.
Knife Type Legality
| Knife Type | Status | Details |
|---|---|---|
| Switchblades | Restricted | M.G.L. ch. 269 § 10(b) formerly banned all switchblades with blades over 1.5 inches. In Commonwealth v. Canjura (2024), the SJC ruled the ban unconstitutional under the Second Amendment. Subsequent 2025 legislation (St. 2025, c. 14) established new conditions: adults 21+ may carry automatic knives with blades under 3 inches. Sale to minors remains prohibited. § 12 restricts manufacturing and selling switch knives. |
| Balisongs / Butterfly Knives | Unclear | Not specifically named in § 10(b). The statute targets knives with 'automatic spring release' mechanisms, which does not describe a balisong's manual flipping mechanism. However, prosecutors have attempted to classify balisongs under the 'device or case which enables a knife with a locking blade to be drawn at a locked position' provision. No published Massachusetts appellate case law directly addresses balisong legality. Double-edged balisongs would be illegal under the 'knife having a double-edged blade' prohibition. Statute: 10. |
| Disguised Knives | Restricted | § 12 explicitly prohibits the manufacture and sale of 'sword canes' and 'pistol canes.' § 10(b) prohibits carrying stilettos, daggers, and dirk knives, which encompass many disguised blade categories. Owning a disguised knife is not explicitly prohibited, but selling one in Massachusetts violates § 12 and carrying one that qualifies as a dagger, stiletto, dirk, or double-edged blade violates § 10(b). |
| Assisted-Opening | Restricted | Massachusetts has not adopted the federal 'bias toward closure' distinction. § 10(b) prohibits 'any knife having an automatic spring release device by which the blade is released from the handle.' Because assisted-opening knives use a spring mechanism, Massachusetts law may treat them as falling within the 'automatic spring release' language. The Canjura ruling and 2025 legislation addressed automatic knives generally, so the new 3-inch/21+ framework likely applies to assisted-opening knives as well, but this has not been explicitly confirmed. Statute: 10. |
| Ballistic Knives | Illegal | Explicitly listed as per se prohibited in both § 10(b) (carrying) and § 12 (manufacturing/selling). § 10(b) prohibits 'any ballistic knife, or any knife with a detachable blade capable of being propelled by any mechanism.' Unlike switchblades, ballistic knives were not addressed by the Canjura ruling or 2025 legislation. First offense: 6 months to 2.5 years jail. |
Relevant Statutes(2)
Legal Disclaimer
This information is provided for general educational purposes and should not be construed as legal advice. Laws change frequently and local ordinances may impose additional restrictions beyond state law. Always verify with official state sources before making decisions about knife carry or ownership. KnifeInformer is not a law firm — consult a qualified attorney for specific legal questions.
