Abstract: Corrosion, loosening and reusability problems incurred with prior art lock washers are eliminated in a lock washer having a planar washer body (10) formed of a thin sheet of resilient metal. A central aperture (18) is locate in the body (10) and is adapted to receive the shank (42) of a bolt to which a nut (40) is to be attached and locked. First and second lock tabs (14), (16) are formed in the body (10) radially outward of the central aperture (18) and are the sole lock tabs on the body (10). Each of the tabs (14), (16), has a radially inwardly facing, straight free edge (30) displaced to one side of the plane of the body (10). Each of the edges (30) is transverse to a radius of the body (10) and the lock tabs (14), (16) are angularly spaced by more than 90.degree. and less than 180.degree. such that when one free edge 30 is engaging the flat (50) of a nut (40), the other free edge (30) will be underlying a point (52) of the nut (40), between two adjacent flats (50) thereof.