Weapons laws in Texas are found in Chapter 46 in the Penal Code.
From the defintions to that chapter, we find:
6) "Illegal knife" means a:
(A) knife with a blade over five and onehalf inches;
(B) hand instrument designed to cut or stab another by being thrown;
(C) dagger, including but not limited to a dirk, stiletto*, and poniard;
(D) bowie knife;
(E) sword; or
(F) spear.
(7) "Knife" means any bladed hand instrument that is capable of inflicting serious bodily injury or death by cutting or stabbing a person with the instrument.
(11) "Switchblade knife" means any knife that has a blade that folds, closes, or retracts into the handle or sheath, and that:
(A) opens automatically by pressure applied to a button or other device located on the handle; or
(B) opens or releases a blade from the handle or sheath by the force of gravity or by the application of centrifugal force.
So, as long as your knife is less that 5 and one-half inches, and isn't a switchblade or butterfly knife, you should be okay.
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