A wire grid polarizer (WGP) can have a conformal-coating to protect the WGP from oxidation and/or corrosion. The conformal-coating can include a barrier layer with at least one: of aluminum oxide, silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, hafnium oxide, and zirconium oxide. A method of making a WGP can include applying the barrier layer over ribs of a WGP by vapor deposition.