Abstract: A knife and sheath system includes a knife with a protrusion on its blade and a sheath having a blade guard with a pocket for the knife blade and a protrusion that extends in to its pocket and cooperates with the knife's protrusion. Additionally, a resilient action is positioned on the blade guard across from the protrusion and attaches to the blade guard at one end. When removing or inserting the knife, the action temporarily displaces, returning to its original shape once the knife is fully seated in the sheath or entirely removed. When fully seated in the sheath, the action locks the knife in place by applying force on the knife in the direction of the sheath protrusion. The sheath optionally also includes sheath supports on opposing sides so that a user can attach the sheath to his gear on either his left or right side.