An organic light-emitting display device includes: a substrate; pixels on a first side of the substrate, each of the pixels comprising a first region for emitting light and a second region for transmitting external light; pixel circuits on the first regions of the pixels, each of the pixel circuits comprising at least one thin film transistor; an insulating layer covering the pixel circuits; first electrodes on the insulating layer, spaced from each other on the first regions, and electrically connected to the pixel circuits; a second electrode opposite the first electrodes and formed throughout the first and second regions of all the pixels; an organic layer between the first electrodes and the second electrode; a sealing member facing the first side of the substrate; and an anti-reflection layer located on at least one of a second side of the substrate or an outer side of the sealing member.