A display device includes a first substrate defining a top surface thereof, a bottom surface thereof facing the top surface, and side surfaces thereof connecting the top and bottom surfaces to each other. The side surfaces included: a first side surface defined by: a first patterned surface including a first pattern of which a length thereof extends in a diagonal direction in a plan view of the first patterned surface, and a second patterned surface which extends obliquely from an upper end of the first patterned surface, the second patterned surface including a second pattern of which a length thereof extends in a perpendicular direction from the upper end of the first patterned surface in a plan view of the second patterned surface.