An OLED device according to an example embodiment includes an organic light-emitting element between a lower substrate and an upper substrate. At least a part of a side surface of the upper substrate has a reverse-tapered shape configured to reduce damage to the lower substrate caused by deformation of the upper substrate due to an external impact. Accordingly, reliability issues resulting from a short circuit or burnt lines due to the deformation of the upper substrate may be resolved, improving overall reliability and productivity of an OLED device.