A display device includes a first substrate; light-emitting elements disposed on the first substrate; an encapsulation film covering the light-emitting elements; a second substrate facing the first substrate; a first outermost film disposed on the second substrate to face the encapsulation film and including AOXNY (where A is a metal or non-metal element and X>Y); and a filler material disposed between the encapsulation film and the first outermost film and placed in direct contact with the first outermost film.