Abstract: A cycloaliphatic epoxy compound in combination with a 2-hydroxy-substituted benzophenone compound and a polyalkyl-substituted dipiperidine compound provides a UV stabilizer that exhibits synergistic behavior. The compounds can be formulated into a composition that is coated on, or impregnated into, the surface of a plastic article or, alternatively, they can be incorporated into a thermoplastic composition which can be thereafter molded into a shaped article. The stabilizer combination succeeds in upgrading the resistance of polyphenylene ether resins and blends against the photo-deteriorative effects of sunlight and bright indoor light, for example, fluorescent lighting.