Knives
Mo. Rev. Stat. § 571.010 — a knife is defined, and an ordinary pocketknife up to four inches is not one
In Missouri, the weapons chapter defines a knife as any dagger, dirk, stiletto, or bladed hand instrument readily capable of inflicting serious physical injury or death by cutting or stabbing, and says a knife does not include any ordinary pocketknife with no blade more than four inches in length.
Where concealment matters. Unlawful use of weapons includes knowingly carrying a knife concealed upon or about the person into any area where firearms are restricted under section 571.107, and exhibiting any weapon readily capable of lethal use in an angry or threatening manner in the presence of one or more persons.
Switchblades and federal law. The prohibited weapons section reaches a switchblade knife only when it is possessed, made, transported, repaired or sold in violation of federal law.
| The assumption | What the law actually does |
|---|---|
| The assumptionEvery pocketknife is a knife under the weapons law | What the law actually doesNot an ordinary pocketknife with no blade more than four inches |
| The assumptionA switchblade is illegal in itself | What the law actually doesThe section reaches one only in violation of federal law |
Federal buildings, courthouses, airports, schools and private property with its own rules are separate questions, and so are court decisions on whether a listed knife is protected by the Second Amendment. Whether a particular knife, or a particular way of carrying it, falls inside the section is a question for a licensed Missouri attorney.
Sources for this section (3)
- Mo. Rev. Stat. § 571.010 — Definitions
- Mo. Rev. Stat. § 571.030 — Unlawful use of weapons, offense of
- Mo. Rev. Stat. § 571.020 — Possession, manufacture, transport, repair, sale of certain weapons a crime — exceptions — penalties
Legal information, not legal advice. Verified as of October 2026. Applying it to a particular situation is the work of a licensed Missouri attorney.