Massachusetts Knife Laws: What's Legal to Carry

Massachusetts knife law remained essentially unchanged for nearly seven decades until the courts intervened. If you carry a blade in this state, the rules that applied last year may not apply now, and the regulations in Boston may not match the rules in Springfield.

The 2024 Canjura decision rewrote the legal framework around automatic knives, and 2025 legislation followed with specific guidelines on who can carry what and where. You can legally carry automatic knives under certain conditions, but stilettos and daggers remain banned. Cities impose their own limits, and schools, courthouses, and airports remain entirely off-limits.

Massachusetts Knife Laws at a Glance

• Adults 21 and older can carry automatic knives with blades under 3 inches, including switchblades and out-the-front knives

• Stilettos, daggers, dirks, double-edged knives, and ballistic knives remain banned statewide

• Boston, Cambridge, Worcester, and Malden each have their own local ordinances with stricter limits

• All knives are prohibited in schools, within 300 feet of school grounds, government buildings, courthouses, and airports

• First offense for carrying a prohibited knife can result in 2.5 to 5 years in state prison

• Concealed carry of any knife that could be classified as a dangerous weapon remains risky

The Canjura Decision: What Changed in 2024

The Massachusetts Supreme Judicial Court struck down the state’s ban on automatic knives in 2024. The ban had been in place since 1957, making switchblades illegal to carry in public for nearly 70 years. 

The ruling in Canjura followed the reasoning set by the U.S. Supreme Court’s 2022 decision in New York State Rifle & Pistol Association Inc. v. Bruen, which created a new standard for evaluating weapons restrictions under the Second Amendment.

Justice Serge Georges Jr. wrote in the decision that nothing about the physical qualities of switchblades suggests they are uniquely dangerous. That statement set the tone for how Massachusetts now treats automatic opening mechanisms. The court found the blanket ban unconstitutional, but the ruling did not eliminate all restrictions on knives.

2025 Legislation: The Current Rules

Following the Canjura decision, the Massachusetts legislature passed new laws in 2025 to fill the gap left by the overturned ban. These laws permit ownership and public carry of automatic knives under specific conditions.

The 3-inch blade limit and 21-year age requirement are firm. If you fall outside these parameters, carrying an automatic knife remains a criminal offense.

Knives That Are Still Banned

The Canjura ruling did not legalize all knives. Massachusetts maintains a list of prohibited blades regardless of blade length or intended purpose. Stilettos, daggers, dirks, double-edged-bladed knives, and ballistic knives cannot be carried legally anywhere in the state. These restrictions apply to ownership and carry alike.

The law also prohibits any knife designed primarily for offensive use. This language gives prosecutors flexibility when charging someone with a knife that does not fit neatly into the named categories but was clearly intended as a weapon.

The Dangerous Weapon Classification

Massachusetts law treats certain knives as dangerous weapons, creating criminal liability when they are possessed in specific contexts. Knives fall into this category in several ways. The knives listed above as prohibited are automatically considered dangerous weapons.

Any other knife designed for bodily assault or defense also qualifies. Beyond that, any knife used dangerously can be classified as a dangerous weapon at the time of an arrest or during the commission of a crime.

This classification matters because concealed carry of any knife that could be deemed a dangerous weapon is generally illegal. Carrying a fixed blade under your jacket, for example, creates legal exposure even if the knife itself is otherwise legal to own.

Local Ordinances: City by City Differences

Massachusetts does not have statewide preemption on knife laws. Cities and towns can pass their own ordinances that impose stricter limits than state law. If you carry a knife in urban areas, local rules matter as much as state rules.

Boston

Boston limits blade length to 2.5 inches. Individuals under 18 may not purchase a knife with a blade longer than 2 inches. These restrictions apply throughout the city limits.

Cambridge

Cambridge law prohibits giving or lending a lockback knife to anyone under 18. Adults can carry lock-back knives, but transferring one to a minor creates criminal liability.

Worcester

Worcester applies a 2.5-inch limit if you are found with a knife while being arrested for another crime. The restriction ties blade length to contact with law enforcement rather than general carry.

Malden

Malden prohibits any knife with a blade over 2.5 inches. This limit applies broadly, making it one of the state’s stricter municipal ordinances.

If you carry a pocket knife daily and travel between cities, the lowest standard limit in your regular area becomes your practical ceiling. A 2.5-inch blade keeps you legal in most urban areas of Massachusetts.

Location-Based Restrictions

Specific locations are off-limits for knives regardless of type or blade length. Massachusetts General Laws chapter 269, section 10 (j) prohibits possession of any dangerous weapon in schools and educational institutions. This includes elementary, secondary, college, and university schools. The restriction applies to both buildings and grounds and extends 300 feet beyond the school property lines.

Carrying a knife into these areas is illegal, even for legitimate purposes, unless you have written authorization from the board or officer in charge. This authorization requirement is strict and applies to everyone, including parents, visitors, and employees.

Beyond schools, knives are prohibited in government buildings, courthouses, airports, and other transportation hubs. Security screening at these locations will flag knives, and possession can result in criminal charges.

Penalties for Violations

Massachusetts treats knife violations seriously. The penalties for carrying a prohibited knife or carrying a legal knife in a restricted location can result in years of incarceration.

First Offense

A first offense for carrying a prohibited knife is punishable by imprisonment of not less than 2.5 years and not more than five years in state prison. Alternatively, the sentence can range from 6 months to 2.5 years in jail or in a house of correction.

If the court finds the defendant has no prior felony conviction, the penalty may be reduced to a fine of not more than $50 or imprisonment of not more than 2.5 years in a jail or house of correction.

Second Offense

A second or similar offense carries a minimum of five years and a maximum of seven years in prison.

School Zone Violations

Violations on school grounds are punishable by a fine of up to $1,000, imprisonment for up to one year, or both.

Practical Considerations for Everyday Carry

If you carry a knife daily in Massachusetts, your safest option is to keep the blade length under 2.5 inches, choose a folding knife with a single edge, and avoid any blade that could be considered offensive in design. Stay aware of local ordinances in the cities where you spend time.

Automatic knives are now legal for adults 21 and older, provided the blade is under 3 inches. Still, the 2.5-inch municipal limits in Boston, Worcester, and Malden mean your automatic knife may be legal under state law but still violate city ordinances. Matching your carry choice to the strictest rule in your area helps prevent issues.

Concealed carry remains a gray zone. The dangerous weapon classification gives officers and prosecutors room to charge someone whose knife is otherwise legal but was carried in a manner or context that suggests offensive intent.

What This Means Going Forward

Massachusetts’ knife law is more permissive than it was before 2024, but it remains restrictive. The Canjura decision opened the door to automatic knives, and the 2025 legislation set age and blade-length limits.

At the same time, the prohibited knife categories remain intact, local ordinances create a patchwork of rules across cities, and location-based restrictions make specific spaces completely off-limits.

Understanding the rules requires attention to state law, your local city ordinances, and the places you intend to go. A knife that is legal to carry on a sidewalk in one town may be illegal on school property in every city. The penalties for getting it wrong range from fines to years in prison. If you carry a blade in Massachusetts, knowing the rules is not optional.