A level vial assembly for use in a carpenter's or mason's level. The assembly includes a vial mounting subassembly to be mounted in a level body, consisting of at least a vial holding plate and one or more vials which are mountable therein, and one, or preferably two, bezel-lens subassemblies for protecting the vial. The vial is positioned in the mounting plate between a pair of oppositely directed notches, and is held in position by a tab which extends outwardly from the side of the vial and bears against the holding plate. The tab limits lateral movement of the vial in one direction. The holding plate is mountable within an aperture in the level body. The bezel-lens subassemblies are mountable in the level body aperture on opposite sides of the vials. One of the bezel-lens subassemblies includes a vial support portion adapted to bear against the vial to prevent lateral movement in another lateral direction. The level vial assembly can be easily and precisely mounted to a level body, resulting in a high-quality product at a reasonable cost of assembly.