Disclosed is a transparent organic light-emitting display (OLED) device having improved resolution by changing the layout of sub-pixel regions in a light-emitting area. The device comprises: a substrate having a plurality of pixels, each pixel including: a light emitting area including a first sub-pixel region, a second sub-pixel region, and a third sub-pixel region; and a transmissive area through which external light passes, wherein the transmissive area is surrounded by edges of the first, second and third sub-pixel regions of the pixel; and an organic light-emitting element on thin film transistors in each of the sub-pixel regions, wherein the first sub-pixel region is arranged on a first line of the pixel extending in a first direction, the second sub-pixel region is arranged on a second line parallel to the first direction, and the third sub-pixel region is arranged on a third line extending in a second direction.