A minor can carry a knife in California under the same rules that apply to adults: state law sets no minimum age for knife possession, and whether a particular knife is legal depends on its type, how it’s carried, and where. The practical catch for anyone under 18 is school. Possession rules are far stricter on campus, and a violation can trigger both juvenile court charges and expulsion.
No Minimum Age Under State Law
California’s Penal Code does not include an age-based prohibition on possessing knives. Unlike firearms, there is no statewide statute saying a 15-year-old cannot own or carry a pocketknife. The rules on what knives are legal, how they can be carried, and where they can go apply identically to a 17-year-old and a 40-year-old.
Local governments can add their own layers. Los Angeles, for example, has a municipal ordinance that prohibits selling fixed-blade or locking-blade knives to anyone under 18, and other cities may have similar rules. But those are sale restrictions on retailers, not possession limits on minors. At the state level, the questions are the same for a teenager as for anyone else: what kind of knife is it, is it concealed, and where is it going?
What a Minor Can Legally Carry
The safest option is a non-locking folding pocketknife with a short blade. It can go in a pocket (because a closed, non-locking folder is not a dirk or dagger), it avoids the switchblade ban (because it opens manually), and it stays legal in most locations away from schools and government buildings.
The moment a knife has a locking blade, the rules tighten. On the street, a locked-open folder counts as a dirk or dagger and must be carried openly in a waist sheath to avoid a concealed-carry charge. On school grounds, any locking folder is banned outright regardless of blade length. For a student who carries a knife daily and passes through school property, that effectively prohibits locking blades during school hours.
Fixed-blade knives follow the same logic but stricter. They are always considered dirks or daggers, so they must always be carried openly in a sheath. They are always banned on school grounds. And any fixed blade over four inches is banned in government buildings.
Open Carry Versus Concealed Carry
The biggest dividing line in California knife law is whether a knife is carried openly or concealed. A standard folding pocketknife with a blade that does not lock into position can be carried in a pocket without a legal issue, because the law treats a closed folding knife differently from a fixed blade.
Carrying a concealed “dirk or dagger” is a serious offense. California defines the term broadly: any knife or instrument that can readily be used as a stabbing weapon capable of causing great bodily injury or death. Every fixed-blade knife falls into this category regardless of blade length. A folding knife also qualifies if its blade is exposed and locked open.1California Legislative Information. California Penal Code 16470 A hunting knife in a backpack or a locked-open folder in a jacket pocket both count as concealed dirks or daggers.
The legal way to carry a fixed-blade knife is in a sheath worn openly on the waist, where anyone can see it. Concealing a dirk or dagger is punishable by up to one year in county jail or by a felony prison sentence, which prosecutors can choose between based on the circumstances.2California Legislative Information. California Penal Code 21310
Knives That Are Illegal for Everyone
Some knives are flatly prohibited in California regardless of age or how they’re carried.
- Switchblades with a blade of two inches or longer. It is a misdemeanor to carry one on your person, keep one in a vehicle, or sell one. A switchblade is any knife with a blade that opens automatically by a spring or mechanical device.3California Legislative Information. California Penal Code 21510
- Ballistic knives, which can launch the blade as a projectile. These are illegal to possess, manufacture, import, or sell, and a violation can be charged as a misdemeanor or felony.4California Legislative Information. California Penal Code 21110
- Undetectable knives, meaning any knife made from materials a metal detector cannot find. Commercial manufacture, import for sale, or sale is a misdemeanor.5California Legislative Information. California Penal Code 20810
- Disguised knives hidden inside everyday objects such as belt buckles, lipstick cases, writing pens, and cane swords.
A switchblade with a blade under two inches is not covered by the ban. That’s a narrow exception, but it exists.
Knives on School Grounds
This is where knife law gets especially harsh for minors. California prohibits bringing any of the following onto K–12 public or private school grounds:
- Any dirk or dagger
- Any knife with a blade longer than two and a half inches
- Any folding knife with a blade that locks into place, regardless of blade length
- Any razor with an unguarded blade
A violation is punishable by up to one year in county jail or by a state prison term. The school rule is stricter than general carry law in an important way: a small locking-blade folder that is legal to carry openly on a public street becomes a criminal offense the moment it enters campus. A separate provision makes it a misdemeanor to bring even a razor blade or box cutter onto K–12 school grounds, and these rules extend to school activities off campus as well.6California Legislative Information. California Penal Code 626.10
Suspension and Expulsion
Criminal charges are only half the problem for a student caught with a knife at school. A principal or superintendent is expected to recommend expulsion for a student who possesses a knife or dangerous object that has no reasonable use for the student, with discretion to choose an alternative if the circumstances warrant it. That discretion disappears if a student brandishes a knife at another person. In that case the principal must immediately suspend the student and recommend expulsion, with no option for alternative correction.7California Legislative Information. California Education Code 48915
The Education Code uses its own definition of “knife”: any dirk or dagger, a weapon with a fixed sharpened blade designed for stabbing, a blade longer than three and a half inches, a folding knife with a locking blade, or a razor with an unguarded blade.7California Legislative Information. California Education Code 48915
Brandishing
Even where a knife is legal to carry, drawing or displaying it in a rude, angry, or threatening manner is a misdemeanor carrying a minimum of 30 days in county jail.8California Legislative Information. California Penal Code 417 For a minor at school, brandishing triggers mandatory expulsion proceedings. Outside school, it still results in a misdemeanor charge in juvenile court. A teenager who thinks waving a knife around is funny or intimidating can end up with a record that follows them for years.
Other Restricted Locations
California bans bringing any knife with a fixed or lockable blade longer than four inches into a state or local government building or into any meeting legally required to be open to the public. A violation is punishable by up to one year in county jail or a state prison term.9California Legislative Information. California Penal Code 171b
Federal buildings follow a separate rule. Pocket knives with blades under two and a half inches are permitted; anything larger or more capable falls under the federal prohibition on dangerous weapons in federal facilities.10Office of the Law Revision Counsel. 18 U.S. Code 930 – Possession of Firearms and Dangerous Weapons in Federal Facilities Airport security checkpoints also prohibit knives past the screening area.
How Juvenile Court Handles Violations
When a minor between 12 and 17 is caught violating knife laws, the case goes to juvenile court rather than adult criminal court. The court can declare the minor a ward of the court, which opens the door to probation, community service, counseling, or placement in a juvenile facility.11California Legislative Information. California Welfare and Institutions Code 602
Children under 12 generally cannot be brought into the juvenile delinquency system at all. California limits juvenile court jurisdiction for that age group to extremely serious violent offenses like murder and sexual assault, none of which would typically apply to a knife possession charge.11California Legislative Information. California Welfare and Institutions Code 602 A child under 12 can still face school discipline and confiscation.
Switchblade possession is a straight misdemeanor.3California Legislative Information. California Penal Code 21510 Concealing a dirk or dagger and bringing a prohibited knife onto school grounds can each be charged as either a misdemeanor or a felony, with felony-level consequences more likely where there’s a prior record, the knife was displayed threateningly, or someone was hurt.6California Legislative Information. California Penal Code 626.10
Parental Financial Liability
When a minor uses a knife to injure someone or damage property through willful misconduct, California holds the parents or guardians financially responsible. The statutory cap is $25,000 per incident for injury-related medical, dental, and hospital costs, and a separate $25,000 cap for property damage involving paint or similar defacement. The Judicial Council adjusts these amounts every two years for cost of living, so the current cap may be higher than the base figure in the statute.12California Legislative Information. California Civil Code 1714.1
Parental liability applies on top of whatever juvenile court sanctions the minor faces. A parent whose child brandishes a knife and injures a classmate could be dealing with juvenile court proceedings, school expulsion hearings, and a civil lawsuit at the same time.