Why Are Butterfly Knives Illegal? State-by-State Balisong Laws

Butterfly knives, also known as balisongs, are folding knives with two handles that rotate around the blade. They are legal in most of the United States, but a few states ban them and several more restrict how you can carry one. So why are they illegal anywhere, and what makes these knives so controversial? This article explains the reasons, where the laws stand today, and how they are changing.

The short answer: butterfly knives are illegal in some states because older laws written for switchblades and gravity knives were applied to them. A balisong can be flipped open with one hand in about a second, so those states treat it like an automatic knife. As of our September 2026 review, New Jersey and New Mexico ban them, 8 more states restrict them (California applies its 2-inch switchblade rule), and the other 40 states treat them as legal.

We make custom knives, not laws, so treat everything here as general information, not legal advice.

What Is a Butterfly Knife?

A butterfly knife is a type of folding knife with a distinct design. Unlike traditional pocket knives, a butterfly knife has two handles that swing open to reveal the blade. This unique mechanism allows for quick deployment, making it a favorite among knife enthusiasts and trick performers.

Balisongs have a long history as everyday utility tools. In the United States they became popular with collectors and with flippers, who practice the opening and closing tricks you see in videos. That same one-handed flip is what a few state laws single out, which is where the legal questions start.

State Laws and Legal Restrictions

Knife laws in the U.S. vary from state to state. Most states allow butterfly knives with no special rules, a couple ban them, and several allow ownership but restrict carry. These are the states where a butterfly knife is not simply legal, from our 50-state knife law data:

Butterfly knives are legal in the other 40 states, including Hawaii (legalized in 2024), New York, and Washington. To see switchblade and carry rules side by side, compare all 50 states on our knife laws by state page. Statuses reviewed September 2026.

Legal to own does not always mean legal to carry. North Carolina is a good example: butterfly knives are legal to own there, but concealed carry is restricted, since state law lets only an “ordinary pocket knife” be carried concealed. See North Carolina knife laws for the details.

Why Are Butterfly Knives Illegal in These States?

The reasons come down to how older knife laws were written:

• Comparison to Switchblades: Many knife laws were aimed at knives that open fast with one hand. A balisong flips open in one motion, so some states fold it into those rules. California and New Mexico apply their switchblade rules to balisongs, and New Jersey treats them as gravity knives.
• Court Decisions: In some states the butterfly knife’s status comes from the courts rather than the statute. In New Mexico, State v. Riddall (1991) held that butterfly knives fall within the switchblade prohibition. Delaware’s law does not name them and its courts have not ruled, which is why we list carry there as a gray area.
• Safety Concerns: Flipping takes practice, and beginners do cut themselves. Supporters of the remaining limits often point to that injury risk.

How to Legally Own a Butterfly Knife

If you’re interested in owning a butterfly knife, it’s crucial to research local laws. Here are some tips to stay within legal boundaries:

• Check State and Local Laws: Always verify whether butterfly knives are legal in your state, and check city rules too, since some cities add their own. Laws can change, so staying updated is important.
• Know the Difference Between Ownership and Carrying: Some states allow possession but not concealed carry. Understanding this distinction can prevent legal trouble.
• Consider Trainer Knives: If you’re interested in flipping tricks but live where butterfly knives are illegal, trainer knives (dull, non-sharpened versions) may be an option, but check how your state’s law defines a knife first.

What Is the Future of Butterfly Knife Laws?

The direction is toward legality. New York’s 2019 gravity-knife repeal left butterfly knives generally legal there. Hawaii legalized them in 2024, following the Ninth Circuit’s Teter v. Lopez decision on its ban. In Massachusetts, the state’s top court struck down the switchblade carry ban in August 2024, though that ruling addressed switchblades, and butterfly knives there remain restricted to carry.

For those who want to stay informed, checking legal resources and following advocacy groups can help track any changes in legislation. Each of our state pages shows the date its status was last reviewed.

Check Your State’s Knife Rules

Knife law changes state by state. Check the rules where you live, for example Texas, Missouri, Wisconsin, or California, or find any state in our 50-state knife law guide. For the national picture, read our guide to knife laws in America.

What Are the Key Takeaways?

Butterfly knives are legal in most states. A few states restrict them because older switchblade and gravity-knife laws were applied to them, and two ban them outright. The trend is toward legality, but laws keep changing, so check your state’s current rules before you buy or carry one.