Abstract: An armrest cover for a lawn chair or other similar outdoor chair. The armrest cover is constructed so that it remains cool when exposed to direct sunlight and high temperatures. The armrest cover includes an elongated body having a flat lower surface so that the body can be positioned directly on the surface of an armrest of a chair. The body is composed of a cushioned or padded material so as to provide comfort to a user. A heat cover is removably securable to the body, wherein the heat cover can be removed when the chair is desired to be used, such that heat cover prevents the body from increasing in temperature. The body further includes one or more pairs of straps thereon, wherein the straps can be secured around the armrest of the chair so as to secure the armrest cover thereon.