Navigating Massachusetts Knife Laws: A Comprehensive Guide to Ownership, Carry, and Recent Legal Changes

Executive Summary

Massachusetts knife laws present a complex and multifaceted legal landscape, characterized by a blend of specific prohibitions, restrictions on carrying, and limitations based on location. The primary legislative authority governing these regulations is Massachusetts General Laws (M.G.L.) Chapter 269. Historically, the Commonwealth maintained stringent regulations on various knife types, particularly automatic knives, reflecting a long-standing policy approach to public safety and weapon control.

A significant shift in this legal framework occurred on August 27, 2024, with the Massachusetts Supreme Judicial Court’s (SJC) landmark ruling in Commonwealth v. Canjura. This decision, grounded in the Second Amendment of the United States Constitution, effectively invalidated the state’s nearly 70-year-old ban on automatic knives. This judicial action created a new legal precedent, compelling a re-evaluation of prior understandings of knife legality in the state.

In the wake of the Canjura ruling, new legislation in 2025 further clarified the legal status of automatic knives. This subsequent legislative action permits their ownership and public carry under specific, newly established conditions, including defined blade length and age restrictions. This two-stage evolution—judicial invalidation followed by legislative re-regulation—illustrates a dynamic interplay between constitutional interpretation and statutory adjustments. The SJC’s decision in

Canjura served as a direct catalyst for these subsequent legislative changes, demonstrating how judicial pronouncements on constitutional rights can necessitate and shape legislative responses, leading to an evolving rather than static legal environment. This development aligns Massachusetts more closely with a broader national trend where Second Amendment challenges, particularly those following the Bruen decision, are reshaping state-level weapon laws to encompass “arms” beyond traditional firearms.

Despite these notable changes concerning automatic knives, many restrictions persist. Prohibitions remain in effect for certain “per se” dangerous knives, such as stilettos, daggers, and ballistic knives. Regulations on concealed carry continue to be stringent, and strict limitations apply to knife possession in sensitive locations, including schools, universities, and government buildings. Furthermore, the absence of statewide preemption means that local ordinances can impose stricter rules than state law, adding an additional layer of complexity for residents and visitors. Violations of Massachusetts knife laws can result in severe penalties, including mandatory minimum sentences, substantial fines, and imprisonment. A thorough understanding of these intricate legal nuances is therefore essential for ensuring compliance and avoiding legal repercussions.

Foundational Principles of Massachusetts Knife Law

Introduction to Massachusetts General Laws Chapter 269, Sections 10 and 12

The bedrock of Massachusetts knife regulation is found within Massachusetts General Laws Chapter 269. Specifically, Section 10(b) is the primary statute that delineates prohibitions on the possession and carrying of various knife types. This particular subsection is renowned for its intricate and expansive nature, often described as a single sentence comprising nearly 400 words. Its comprehensive phrasing aims to cover a wide array of dangerous weapons, including specific categories of knives, whether carried on one’s person or under control in a vehicle.

Complementing Section 10, Chapter 269, Section 12, addresses the manufacturing and sale of certain prohibited knives. Historically, this section has restricted the production and commercial exchange of items such as dirk knives, switch knives, and automatic knives with blades exceeding 1.5 inches. The legal landscape concerning automatic knives under Section 12 has been significantly altered by the

Commonwealth v. Canjura ruling and subsequent legislative actions in 2025, which have redefined their permissible status.

Defining “Dangerous Weapons”: Understanding the Role of Knife Type, Intent, and Circumstances

Massachusetts law employs a dual classification system for knives, distinguishing between those that are “per se” dangerous weapons and those that may be deemed dangerous based on the context of their possession or use. “Per se” dangerous weapons are knives inherently prohibited by their design, irrespective of the carrier’s intent. These include stilettos, daggers, ballistic knives, dirk knives, and knives with double-edged blades. These specific designs are considered inherently dangerous due to their primary purpose as weapons, reflecting a clear legislative determination that their potential for misuse outweighs any common utility. This design-based restriction means that merely possessing or carrying these types of knives is illegal, placing a strict burden on individuals to recognize and avoid such specific designs.

Beyond these inherently prohibited types, a knife not explicitly listed as “per se” illegal can still be classified as a “dangerous weapon” under Massachusetts law. This classification hinges on two critical factors: the intent of the individual carrying the knife and the surrounding circumstances. A knife becomes a dangerous weapon if it is carried with the intent to use it unlawfully against another person. This emphasis on the carrier’s purpose makes intent a pivotal factor in the legal classification of a knife. Furthermore, possession of a knife during a “breach or disturbance of the public peace” can also lead to its classification as a dangerous weapon. For example, judicial precedent has shown that even a seemingly minor infraction, such as driving with an expired registration, can be interpreted as a disturbance of the peace, thereby justifying an arrest and subsequent search that could lead to a dangerous weapon charge if a knife is found. This highlights that legality is not solely about the object itself, but also about the operator’s actions and the environment in which the knife is present. This dual classification system, combining design-based prohibitions with situational prohibitions based on intent or circumstances, introduces a highly subjective element into enforcement, where the context of possession is as critical as the knife’s physical characteristics.

The Absence of Statewide Preemption: Implications of Local Ordinances

A critical aspect of Massachusetts knife law is the absence of statewide preemption. This means that unlike some other states where state law overrides local regulations, municipalities within Massachusetts retain the authority to enact their own ordinances concerning knives that are more restrictive than the general state law.⁴ This legislative choice by the state directly results in a fragmented legal landscape.

This lack of uniformity creates what is often referred to as a “patchwork problem” for residents and visitors. Individuals must not only be familiar with state-level prohibitions and regulations but also research and comply with potentially different or more stringent local ordinances in each city or town they visit or reside in. Major cities such as Boston and Salem are explicitly noted as having their own knife ordinances. For instance, Boston imposes a specific blade length limit of 2.5 inches  and prohibits individuals under the age of 18 from purchasing knives with blades longer than two inches. Similarly, Cambridge has an ordinance making it illegal to give or lend a lock-back knife to anyone under 18. This fragmentation significantly increases the complexity of legal compliance and elevates the risk of unintentional violations for individuals traveling within the state. It underscores a common tension in U.S. law between state authority and local autonomy, where the exercise of local control can lead to considerable practical challenges for citizens attempting to navigate the legal requirements.

Prohibited and Restricted Knife Types

Massachusetts law clearly defines and restricts several categories of knives, classifying them as “per se” illegal regardless of the possessor’s intent or the circumstances of their carry. These explicit prohibitions are detailed primarily under M.G.L.A. Chapter 269, Section 10(b).

Detailed Descriptions of Per Se Illegal Knives

The following knife types are specifically prohibited from being carried on one’s person or under one’s control in a vehicle in Massachusetts:

• Stiletto: This refers to a knife characterized by a slender, tapering blade primarily designed for stabbing. Its design emphasizes penetration over cutting, making it inherently a thrusting weapon.
• Dagger: A dagger is typically a short, pointed knife with one or more sharp edges, commonly used for stabbing. It is often associated with close-quarters combat and is explicitly listed among prohibited items.
• Ballistic Knife: Defined as a knife with a blade that can be projected or ejected from the handle, often via a spring-operated mechanism. These knives are designed for projectile use and are strictly prohibited.
• Dirk Knife: A dirk is generally described as a long, straight-bladed dagger. Similar to daggers, their design is primarily for stabbing, and they fall under the per se prohibition.
• Double-Edged Blade: This category encompasses knives that feature two sharpened cutting edges. While many flat blades might technically have two sides, the statute specifically targets those designed with two
  sharpened or effective cutting edges. The intent of the Massachusetts statute is to address blades that are sharpened on both sides, distinguishing them from knives where one edge might be the full thickness of the blade.

These enumerated items are consistently identified as “per se dangerous weapons” within the Massachusetts legal framework.⁸ This explicit listing of specific knife types as inherently prohibited, irrespective of intent, signifies a clear legislative determination to ban these designs due to their perceived primary purpose as weapons. This approach contrasts with the subjective “dangerous weapon” classification, which depends on the carrier’s intent or surrounding circumstances. The “per se” prohibition reflects a legislative judgment that these particular knife designs are inherently dangerous and lack legitimate common purposes that would outweigh the risk of their misuse. This design-based restriction means that merely possessing or carrying these specific knife types is illegal, irrespective of how one intends to use them or where they are. This simplifies enforcement for these categories while placing a strict burden on individuals to know and avoid these specific designs.

Analysis of Devices Enabling Quick-Draw of Locking Blades

Beyond specific knife types, M.G.L.A. 269 § 10(b) also prohibits “a device or case which enables a knife with a locking blade to be drawn at a locked position”.⁷ This provision was originally conceived to target quick-draw sheaths, which were marketed for manually opened lock-blade knives, such as the iconic Buck Model 110.⁸ The legislative intent was to prevent the rapid deployment of a locked blade from a carrying device, thereby mitigating the perceived danger of such immediate access.

However, the application of this prohibition has seen attempts at expansive interpretation by prosecuting officials. There have been instances where this statutory language has been applied to one-hand manual knives featuring “thumb studs” or to “butterfly” knives, even in the absence of an associated sheath or external device.⁸ This demonstrates a potential for ambiguity and overreach in the interpretation of the “quick-draw device” prohibition. While the original legislative intent was focused on external devices, the attempts to extend this to inherent design features like thumb studs or the mechanics of butterfly knives create a risk for owners of common, non-automatic one-hand opening knives. It is important to note that some individuals mistakenly believe that unassisted, manual, one-hand operability itself is restricted, but the law does not generally impose such a blanket prohibition.²⁰ This situation highlights a recurring challenge in legal interpretation where statutory language, particularly older statutes, struggles to keep pace with technological advancements in knife design and opening mechanisms. Such ambiguity can lead to legal uncertainty and the potential for arbitrary enforcement, underscoring the need for clearer legislative definitions or definitive judicial clarification to ensure predictable application of the law.

Table 1: Massachusetts Prohibited Knife Types

Type de couteau	Description	General Legal Status (Carry/Possession)
Stiletto	Slender, tapering knife designed for stabbing.	Per Se Illegal
Dagger	Short, pointed knife with a sharp edge, typically used for stabbing.	Per Se Illegal
Couteau balistique	Knife with a blade that can be projected or ejected from the handle.	Per Se Illegal
Dirk Knife	Long, straight-bladed dagger.	Per Se Illegal
Double-Edged Blade	Knife with two sharpened cutting edges (not merely two sides).	Per Se Illegal
Device Enabling Quick-Draw of Locking Blade	Any device or case allowing a locking-blade knife to be drawn in a locked position.	Per Se Illegal (Application may extend to some one-hand openers by prosecutors) 7

Note: This table summarizes per se prohibited knives and devices. Other knives may be deemed “dangerous weapons” based on intent or circumstances. The legal status of automatic knives has recently changed, as detailed in Section IV.

The Evolving Legality of Automatic Knives (Switchblades)

The legal status of automatic knives, commonly known as switchblades, in Massachusetts has undergone a profound transformation. Historically, these knives were largely prohibited, a stance that reflected a national legislative trend influenced by public perception and concerns over their rapid deployment.

Historical Context of the Ban and Previous Blade Length Restrictions

Prior to recent legal developments, Massachusetts General Law Chapter 269, Section 10(b), explicitly prohibited “any knife having an automatic spring release device by which the blade is released from the handle” if its blade was longer than one and a half (1 ½) inches. This restriction effectively banned most practical automatic knives, aligning Massachusetts with a number of other states that enacted similar prohibitions during the “switchblade legislative hysteria” of the 1950s. Assisted opening knives, which require some manual exertion but use a spring to complete the opening, were also prohibited if their blades exceeded 1.5 inches. This broad prohibition meant that possession, carry, and sale of such knives were generally illegal, leading to significant penalties.

In-Depth Analysis of the Commonwealth v. Canjura (August 27, 2024) Ruling

A pivotal moment occurred on August 27, 2024, when the Massachusetts Supreme Judicial Court (SJC) issued its groundbreaking ruling in Commonwealth v. Canjura. This unanimous decision concluded that the state’s nearly 70-year-old ban on automatic knives violated the Second Amendment right to bear arms. The case originated from a 2020 prosecution where Boston police found a “firearm-shaped knife with a spring-assisted blade” on David E. Canjura, leading to a charge of carrying a dangerous weapon under M.G.L. 269 § 10(b).

The SJC’s analysis in Canjura was thorough and directly addressed the Second Amendment implications, particularly in light of the U.S. Supreme Court’s Heller and Bruen decisions. The Commonwealth argued that the Second Amendment only protected firearms, a contention the SJC swiftly rejected. The Court emphasized that Second Amendment protections extend beyond firearms, encompassing other “arms” typically possessed by law-abiding citizens for lawful purposes. The SJC conducted an extensive historical analysis, noting the widespread presence and utility of pocket knives in 18th-century Massachusetts, not only for self-defense but also for essential roles like food preparation and crafting. This historical context was crucial in determining that switchblades qualify as “arms” for Second Amendment purposes, thereby presumptively protecting their carry.

The SJC then examined whether the ban on switchblades was consistent with the nation’s historical tradition of arms regulation. The Commonwealth attempted to demonstrate historical prohibitions on switchblades or their “historical twins.” The SJC, in a novel approach, defined “historical twin” for switchblades as laws specifically targeting switchblades or pocket knives in general. The three laws presented by the Commonwealth were categorically rejected, as none directly addressed switchblades or general pocket knives. The Court noted that previous cases allowing broader “historical twin” legislation were inapplicable because the knives targeted were too dissimilar to pocket knives and switchblades.

Finally, the Commonwealth argued that switchblades were not in “common use” and were “dangerous and unusual” – a standard from Heller and Bruen applied to items like sawed-off shotguns. The SJC refuted this, finding that switchblades were in common use, citing that only seven states and the District of Columbia still prohibited them. The Court also determined that while all weapons are dangerous, switchblades were not “uniquely dangerous” in a way that disproportionately outweighed their utility in self-defense. The SJC’s refusal to grant the Commonwealth a request for further briefing underscored the finality and conviction of their decision, effectively striking down Massachusetts’ long-standing switchblade ban. This ruling represents a significant victory for knife owners, achieved through judicial means that would have been highly improbable via the state legislature, given Massachusetts’ political landscape. It also provides a robust analytical framework for future litigation on similar issues, potentially impacting the Federal Switchblade Act.

Current Legal Status: Permitted Blade Length and Age Requirements Post-Ruling

In the wake of the Canjura ruling, Massachusetts’ legal framework for automatic knives has been updated through new legislation in 2025. While the SJC’s decision effectively removed the blanket prohibition, subsequent legislative action has introduced specific conditions for their legal ownership and public carry. Under the revised rules, automatic knives that open with a button or switch are now permitted for personal use, including public carry, provided their blade length is less than 3 inches. This new blade length restriction contrasts with the previous 1.5-inch limit that applied to prohibited automatic knives.

Regarding age, the legal possession of switchblade knives is now restricted to adults aged 21 and older. This establishes a higher age threshold for automatic knives compared to general knife possession, which is typically 18 years or older for public carry. Knives exceeding the 3-inch blade limit or those specifically intended for dangerous uses, such as concealed carry without proper authorization, remain illegal unless special permits are obtained.

It is important to recognize that this represents a two-stage regulatory change. The SJC’s decision in Canjura invalidated the old ban, thereby creating a legal vacuum where automatic knives were no longer per se illegal under the prior statute. This judicial action then prompted subsequent legislative re-regulation, establishing new, constitutionally compliant parameters for their possession and carry. This illustrates a crucial causal relationship where the court’s decision directly influenced the need for and nature of legislative action.

Considerations for Manufacturing and Sale in Light of the Ruling

The Canjura ruling and the subsequent 2025 legislation have also impacted the manufacturing and sale of automatic knives within Massachusetts. Previously, M.G.L.A. 269 § 12 prohibited the manufacturing and selling of switch knives or automatic knives with blades over 1.5 inches. With the striking down of the ban and the introduction of new regulations, knife manufacturers and sellers can now legally offer automatic knives to Massachusetts consumers, provided these knives comply with the new 3-inch blade length limit and other conditions. This is expected to lead to a wider variety of automatic knife options becoming available for sale within the state, both from local retailers and online sources.

However, despite the eased restrictions on ownership and carry, the law maintains a strict stance on the sale and distribution of switchblades, particularly to minors. Furthermore, while state law has evolved, local jurisdictions may still impose stricter regulations on the possession and carry of switchblades, necessitating awareness of both state and local guidelines for compliance.

The SJC’s reasoning in Canjura—that knives are “arms” for Second Amendment purposes and that switchblades are in “common use” and not “uniquely dangerous”—sets a significant precedent. This precedent extends beyond Massachusetts, potentially impacting the Federal Switchblade Act, which regulates interstate commerce of automatic knives. This ripple effect of the

Bruen decision, extending Second Amendment protections to knives, signifies a broader trend in constitutional law.

Table 3: Massachusetts Automatic Knife Regulations (Post-Canjura & 2025 Legislation)

Aspect	Pre-Canjura (Prior to Aug 27, 2024)	Post-Canjura (Aug 27, 2024 Ruling)	2025 Legislation (Effective 2025)
Legal Status (Possession/Carry)	Generally Prohibited (Automatic knives with blade > 1.5 inches)	Ban Struck Down (Presumptively protected under Second Amendment)	Permitted for Personal Use & Public Carry
Limite de la longueur de la lame	1.5 inches (for automatic knives)	No specific blade length limit established by SJC ruling itself	Less than 3 inches
Age Restriction	No specific age for automatic knives (general knife age 18+)	No specific age limit established by SJC ruling	21 years and older
Manufacturing/Sale	Prohibited for blades > 1.5 inches	Ban on manufacturing/sale of blades > 1.5 inches likely invalidated by ruling’s logic	Permitted for knives meeting new criteria; strict stance on sale to minors
Legal Basis	M.G.L.A. 269 § 10(b) & § 12	Commonwealth v. Canjura (SJC ruling)	New legislation in response to Canjura

Regulations on Carrying Knives

The manner in which a knife is carried in Massachusetts is subject to specific regulations, distinguishing between open and concealed carry, and addressing possession within vehicles. These regulations are often intertwined with the “dangerous weapon” classification, where intent and circumstances play a crucial role.

Open Carry

Open carry of knives in Massachusetts is generally permitted for knives that are legal to own. This means that for knives not explicitly prohibited by design (as outlined in Section III) and not deemed illegal due to blade length or automatic mechanism (as per Section IV), carrying them openly is typically allowed. However, this general permissibility comes with a significant caveat: the open display of large knives or blades in public places can potentially be interpreted as a “breach of the peace” or a “threat”. This interpretation is particularly likely if the knife is carried in a manner that suggests an intention to use it as a weapon.

This aspect of the law introduces a subjective element into what might otherwise seem straightforward. Even if a knife is legally owned and openly carried, the context, the individual’s demeanor, and the perception of law enforcement can transform a permissible act into a legal issue. This underscores the importance of how a knife is carried, not merely what knife is carried. The potential for a “breach of peace” charge means that individuals must be acutely aware of their surroundings and the potential reactions of others, as well as the subjective interpretation by authorities. This serves as a reminder that even legal actions can incur legal consequences if they are perceived to disturb public order or safety.

Concealed Carry

Concealed carry laws in Massachusetts are considerably stricter than those for open carry. It is generally considered illegal to carry a knife concealed upon one’s person. This prohibition is particularly enforced if the knife falls under the category of being a “dangerous weapon” or if the individual carrying it intends to use it unlawfully against another person. The law’s stringent stance on concealed carry aims to prevent the hidden possession of items that could be readily used for harmful purposes without warning.

While the general rule is against concealed carry of dangerous weapons, the law’s application can be nuanced. For instance, some sources indicate that concealed carry is “not an issue” , which appears to contradict the general prohibition against concealed carry of dangerous weapons. This apparent discrepancy highlights the complexity of Massachusetts knife laws and the potential for differing interpretations or specific contexts. It is crucial to understand that even if a knife is not “per se” illegal, concealing it can elevate its legal risk, especially if it could be classified as a “dangerous weapon” based on its design (e.g., daggers, dirks, stilettos, double-edged blades, which are often implicitly designed for concealment and quick access) or the carrier’s intent. The mere act of concealing a knife can contribute to the perception of unlawful intent, making it a higher-risk activity than open carry, even for otherwise legal knives.

Carrying in a Vehicle

The regulations concerning carrying knives extend to their presence within a vehicle. M.G.L.A. 269 § 10(b) explicitly states that prohibitions apply not only to carrying a knife on one’s person but also to knowingly having it under one’s control in a vehicle. This means that the same restrictions applicable to personal carry of prohibited knife types (e.g., stilettos, daggers, ballistic knives) also apply when these knives are found within a vehicle.

Furthermore, similar to personal carry, a knife that is not “per se” illegal can still be considered a “dangerous weapon” if found in a vehicle under circumstances indicating an intent to use it unlawfully or during a breach of the public peace.⁸ This broad application means that individuals must exercise the same caution regarding knife types and intent whether they are carrying a knife on their person or transporting it in a vehicle. The legal framework treats vehicle possession with similar gravity to personal carry, reflecting a comprehensive approach to regulating dangerous weapons in public spaces and conveyances.

Location-Specific Restrictions

Massachusetts law imposes strict prohibitions on carrying knives in certain designated “sensitive locations,” irrespective of the knife’s general legality or the manner of carry. These restrictions are a clear reflection of public policy aimed at enhancing safety in vulnerable environments. This consistent prohibition across various sensitive locations serves as a strong cautionary principle for knife owners.

Schools and Educational Institutions

Knives are strictly prohibited from all schools and educational institutions in Massachusetts, encompassing elementary levels through university campuses. M.G.L.A. 269 § 10(j) specifically prohibits the possession of any “dangerous weapon,” which almost certainly includes knives, in any building or on the grounds of any elementary or secondary school, college, or university without the written authorization of the board or officer in charge. This applies broadly to all types of knives, including household and utility knives, craft knives, and even pocket or folding knives.¹¹ The objective behind these stringent regulations is to prevent any potential harm that could arise from the presence of knives around children and adolescents, acknowledging that school-aged individuals may lack the discretion necessary for carrying weapons. Violating these restrictions can lead to significant legal penalties, including fines and imprisonment.

Government Buildings and Courthouses

Carrying knives is strictly prohibited in government buildings and courthouses throughout Massachusetts. These locations are considered secure areas where the presence of weapons, including knives, is restricted to maintain public order and safety for officials and citizens alike. The General Services Administration (GSA) also regulates pocket knife possession on federal property, including federal buildings and courthouses, typically prohibiting them unless there is a legitimate occupational need. This underscores a consistent policy across different levels of government to create secure environments free from potential threats.

Airports and Other Transportation Hubs

Airports and other transportation hubs are also designated as strictly prohibited locations for carrying knives. M.G.L.A. 269 § 12F specifically addresses the possession or placement of a cutting device or prohibited weapon in airport secure areas, outlining the associated punishments. These regulations are critical for ensuring the safety and security of travelers and personnel within transit systems, reflecting both state and federal concerns over potential threats in high-traffic, enclosed environments.

Public Gatherings

Public gatherings, such as concerts, festivals, rallies, and parades, are regulated locations where carrying knives is explicitly prohibited. These events typically draw large crowds and involve close proximity, which increases the potential for violence or accidents if weapons are present. Consequently, Massachusetts knife laws explicitly prohibit the possession of any type of knife or other potentially dangerous weapon at such public gatherings to mitigate these risks. Individuals planning to attend such events are advised to check venue guidelines in advance to confirm permissible items.

Local Ordinances

As discussed in Section II, Massachusetts does not have statewide preemption for knife laws, allowing local jurisdictions to impose stricter regulations. Major cities like Boston and Salem are known to have their own knife ordinances. For example, Boston has a 2.5-inch blade length limit for carry. This means that even if a knife is permissible under state law, it might be prohibited or subject to further restrictions within specific municipalities. This necessitates that individuals not only understand state laws but also diligently research and comply with local guidelines to ensure full legal adherence.

Age-Based Restrictions

Massachusetts knife laws include specific age-based restrictions, particularly concerning the purchase and public carry of knives. These regulations reflect a broader policy objective to prevent individuals under a certain age from acquiring or possessing knives, given concerns about their level of maturity and discretion.

General Purchase and Carry Age

In Massachusetts, individuals are generally required to be 18 years of age or older to purchase a knife and to carry it in public. The state considers knives as dangerous weapons, and carrying such a weapon with the intent to harm can lead to serious charges, such as assault with a dangerous weapon. This general age requirement applies to public carry, emphasizing that legal responsibility for carrying a knife begins at adulthood. Minors under the age of 18 are generally not allowed to carry knives unless they have a legitimate purpose or reason, such as for education, work, or other lawful activities. This is intended to prevent harm to both the minors themselves and others, acknowledging their potential lack of understanding regarding the consequences of carrying a knife.

Local Variations

Beyond state-level regulations, local jurisdictions in Massachusetts can impose additional age-based restrictions. For instance, in Boston, individuals under 18 years old are prohibited from purchasing knives with blades longer than two inches. This specific local ordinance further restricts access to larger knives for minors within the city. Similarly, in Cambridge, it is illegal to give or lend a lock-back knife to anyone under 18. These local rules demonstrate a layered regulatory approach, where municipalities exercise their autonomy to implement stricter “supply-side” prohibitions aimed at preventing minors from acquiring certain types of knives. This reflects a localized concern about youth maturity and discretion, leading to more granular control over knife sales and transfers to younger individuals.

Minors with Legitimate Purpose

Despite the general age restrictions, minors may be permitted to carry knives if they can demonstrate a “legitimate purpose” for doing so. This exception is typically for activities related to education, work, or other lawful pursuits. For example, a minor working in a trade that requires a utility knife might be permitted to carry it for that specific work purpose. This nuanced approach acknowledges that knives can be essential tools for certain activities, even for individuals under 18, provided their use is within the confines of a clearly defined and lawful scope. However, the burden of proving such a legitimate purpose rests with the minor, and misuse or deviation from the stated purpose could still lead to legal consequences.

Exemptions and Lawful Purposes

While Massachusetts knife laws are generally restrictive, certain exemptions and allowances for “lawful purposes” exist, reflecting a pragmatic recognition of knives as essential tools for various professional duties and everyday activities.

Exemptions for Law Enforcement Personnel

Members of law enforcement are typically granted exemptions from many of the restrictions imposed on the general public regarding knife possession and carry. These individuals are often permitted to carry weapons, including knives, that are necessary for the performance of their official duties. Specifically, M.G.L.A. 269 § 10(j), which prohibits carrying dangerous weapons on school or university grounds, includes an explicit exception for law enforcement officers. This exemption acknowledges the unique operational requirements and responsibilities of law enforcement.

Clarification of Military Exemptions

The status of military exemptions in Massachusetts knife law presents a point of clarification. While some general sources indicate that members of the military are “usually exempt from many of the restrictions imposed on the general public regarding knife possession and carry” , other more specific sources directly contradict this for Massachusetts. Notably, the American Knife and Tool Institute (AKTI) explicitly states that “No military exemptions are provided in Massachusetts” under M.G.L.A. 269 § 10(j). Given the specific nature of the AKTI’s information regarding Massachusetts statutes, it is prudent to conclude that, unlike law enforcement, military personnel do not have a blanket exemption under Massachusetts knife laws, particularly concerning restrictions in sensitive locations. Military members should be aware that their duty status and whether the items are connected to official activity are critical factors in other jurisdictions, but Massachusetts appears to have a more limited scope of exemption for them.

Professional and Everyday Use Exceptions (“Lawful Purpose”)

Massachusetts law acknowledges that knives are necessary for a variety of everyday activities and certain professional duties. As such, it has carved out exceptions to the general prohibitions, particularly for knives with blades larger than 1.5 inches (prior to the Canjura ruling’s impact on automatic knives). The legality of carrying a knife in these contexts hinges on whether it is being carried for a “lawful purpose”.

Examples of such lawful purposes and natural exceptions include:

• Professional Use: Carrying knives for jobs where they are a common occurrence, such as in farming, various trades (e.g., carpentry, electrical work), or culinary professions. The key determinant is whether the knife is genuinely necessary for the task at hand. Not every knife will qualify as an exception, even if a professional requires knives for their work. For instance, a chef’s knife might be necessary in a kitchen but could still fall outside blade size requirements or be deemed inappropriate for carry outside that specific environment.
• Everyday Utility: Carrying knives for routine tasks such as opening packages, cutting rope, or for food preparation while camping or engaging in other outdoor recreational activities like hunting, fishing, or trapping. For hunting knives, there is a specific allowance to carry blades longer than 2.5 inches if used for legitimate purposes, provided they are carried in a sheath that covers the blade, implying a need for concealment or secure transport.

The critical aspect of these exceptions is that the knife must have a functional purpose, and its use must remain strictly within the confines of that stated purpose. Failure to comply with the stated purpose for carrying the knife can be interpreted as a clear indication of intent to carry an illegal knife, which is a violation under the statute. This introduces a subjective risk, as the burden falls on the individual to demonstrate that their use of the knife is legitimate and within the scope of a lawful activity. This principle highlights that the carrier’s intent plays a significant role in determining the legality of knife possession and carry, even for knives that are generally considered legal.

Penalties for Non-Compliance

Violations of Massachusetts knife laws carry significant legal consequences, ranging from misdemeanors to felonies, with potential for substantial fines and lengthy imprisonment, including mandatory minimum sentences. The severity of penalties often depends on the specific violation, prior criminal history, and aggravating factors.

M.G.L.A. 269 § 10(b) Penalties

The primary statute for carrying dangerous weapons, M.G.L.A. 269 § 10(b), imposes severe penalties for illegal possession or control of prohibited knives (e.g., stilettos, daggers, ballistic knives, double-edged blades, and devices enabling quick-draw of locking blades) on one’s person or in a vehicle. A conviction under this subsection can result in imprisonment in a state prison for not less than two and one-half years nor more than five years, or for not less than 18 months nor more than two and one-half years in a jail or house of correction. Critically, the sentence imposed for such a conviction includes a mandatory minimum of 18 months, during which the individual is ineligible for probation, parole, work release, furlough, or any sentence reduction for good conduct. Prosecutions under this subsection cannot be continued without a finding or placed on file.

For a second or “like” offense, the penalties are even more severe, carrying a minimum of five years imprisonment and a maximum of seven years. This demonstrates a severe legislative stance on repeat offenses involving dangerous weapons.

Felony and Misdemeanor Distinctions

Knife law violations can be classified as either misdemeanors or felonies, depending on the specific offense and its context. While carrying certain prohibited knives might be a misdemeanor, aggravating factors can elevate the charge to a felony. For instance, possession of an unlicensed weapon outside one’s home or business, or possession of a dangerous weapon, carries a mandatory minimum sentence of 18 months in prison. Possessing a firearm (which can include certain knives in some contexts) while committing a felony carries a mandatory minimum sentence of 5 years in prison.

Aggravating Factors

Several factors can significantly increase the severity of penalties:

• Prior Convictions: Individuals with prior felony convictions, misdemeanors punishable by more than two years in jail, violent crimes, or firearms/drug violations are automatically prohibited from obtaining a firearms license and face enhanced penalties for new offenses. A second offense for carrying a dangerous weapon, as noted, increases the minimum sentence.
• Breach or Disturbance of the Public Peace: If a knife, even one not “per se” illegal, is possessed when arrested on a warrant or while committing a “breach or disturbance of the public peace,” the individual is subject to the same range of penalties as for carrying a per se prohibited weapon. This means that the circumstances surrounding the possession can significantly impact the legal outcome.
• School/University Property: A violation of M.G.L.A. 269 § 10(j), which prohibits possession of any “dangerous weapon” on school or university grounds, is punishable by a fine of up to $1,000 and/or two years imprisonment. This highlights the increased penalties for carrying knives in sensitive locations.

The presence of mandatory minimum sentences for certain knife law violations, particularly under M.G.L.A. 269 § 10(b), indicates a severe legislative stance on illegal weapon possession. This consequence underscores the high stakes involved, demonstrating that even seemingly minor violations can lead to significant imprisonment, emphasizing the critical importance of strict adherence to these laws.

Table 2: Key Massachusetts Knife Law Penalties (M.G.L.A. 269 § 10)

Violation Type (M.G.L.A. 269 § 10)	Description	Minimum Imprisonment	Maximum Imprisonment	Other Penalties
Carrying Prohibited Weapon (§ 10(b))	Carrying stiletto, dagger, ballistic knife, dirk, double-edged blade, or quick-draw device on person or in vehicle.	18 months (jail/house of correction)	5 years (state prison)	Ineligible for probation, parole, work release, furlough, or good conduct reduction for 18 months.
Second/Like Offense (§ 10(b))	Subsequent conviction for carrying a prohibited weapon.	5 years	7 years
Possession on School/University Grounds (§ 10(j))	Possession of any “dangerous weapon” (including knives) on school/university property without authorization.	None specified (up to)	2 years	Fine up to $1,000 8
Possession of Unlicensed Weapon (at home/work) (§ 10(h)(1))	Possessing a firearm, rifle, or shotgun without a license/permit in home/place of business.	None specified (up to)	2 years
Possession of Firearm while Committing Felony (§ 18B)	Possessing a firearm while committing a felony.	5 years	Not specified

Note: Penalties can vary based on specific circumstances, judicial discretion within ranges, and the presence of aggravating factors. This table summarizes key penalties but is not exhaustive.

Conclusion and Practical Recommendations

Massachusetts knife laws are characterized by their detailed prohibitions, nuanced carry regulations, and strict location-based restrictions, all underpinned by the overarching framework of Massachusetts General Laws Chapter 269. The legal landscape has recently undergone a significant transformation, particularly concerning automatic knives, due to the Commonwealth v. Canjura SJC ruling in August 2024 and subsequent legislative adjustments in 2025. This evolution has shifted the legal status of automatic knives from prohibited to conditionally permitted, reflecting a broader trend in Second Amendment jurisprudence.

Despite these changes, the core principles of Massachusetts knife law remain robust. Knives such as stilettos, daggers, ballistic knives, dirk knives, and double-edged blades continue to be “per se” illegal. The concept of a “dangerous weapon” extends beyond these explicit prohibitions, encompassing any knife carried with unlawful intent or under circumstances that disturb public peace. The absence of statewide preemption means that local ordinances can impose more stringent rules, creating a complex patchwork of regulations that demand careful attention from individuals. Furthermore, strict bans on knives in sensitive locations like schools, government buildings, and public gatherings persist, underscoring a consistent public safety objective. Violations of these laws carry severe penalties, including mandatory minimum sentences and substantial fines, emphasizing the high stakes involved in non-compliance.

To navigate this intricate legal environment effectively, individuals in Massachusetts are strongly advised to adhere to the following practical recommendations:

1. Understand Prohibited Knife Types: Familiarize oneself thoroughly with the specific knife types that are “per se” illegal under M.G.L.A. 269 § 10(b), such as stilettos, daggers, ballistic knives, dirk knives, and double-edged blades. Avoid possessing or carrying these knives under any circumstances.
2. Stay Informed on Automatic Knife Regulations: Be aware of the updated regulations for automatic knives following the Canjura ruling and 2025 legislation. Ensure any automatic knife owned or carried complies with the new blade length limit (less than 3 inches) and age restrictions (21 years and older).
3. Exercise Caution with Carry Methods: While open carry is generally permitted for legal knives, be mindful that displaying large knives in public can be perceived as a “breach of peace” or a “threat.” Concealed carry of any knife, particularly those that could be deemed a “dangerous weapon,” is generally illegal and carries significant risks.
4. Know Your Local Ordinances: Due to the absence of statewide preemption, always research and comply with local knife ordinances in your city or town, as these may be stricter than state law. This is particularly important in major urban areas like Boston and Salem.
5. Adhere to Location-Based Restrictions: Strictly avoid carrying any knife into prohibited “sensitive locations” such as schools, universities, government buildings, courthouses, airports, and public gatherings, unless explicitly authorized by law (e.g., for law enforcement).
6. Verify Age-Related Requirements: Ensure compliance with age restrictions for purchasing and carrying knives. Remember that local ordinances may impose additional age-based prohibitions or restrictions on lending knives to minors.
7. Carry for Lawful Purpose Only: If carrying a knife for professional duties or everyday utility, ensure its use is strictly within the confines of a legitimate “lawful purpose.” Be prepared to articulate and demonstrate this purpose, as intent can significantly influence the legal classification of a knife.
8. Be Aware of Penalties: Understand the severe criminal charges, mandatory minimum sentences, and fines associated with knife law violations. The consequences of non-compliance are substantial and can include lengthy imprisonment.

Given the complexity and evolving nature of Massachusetts knife laws, particularly with recent judicial and legislative developments, it is highly recommended that individuals with specific questions or concerns consult with a qualified legal professional specializing in Massachusetts criminal or constitutional law. Such consultation can provide personalized advice and ensure full compliance with current regulations, mitigating potential legal risks.