An organic light emitting display device includes: a substrate; a display unit on the substrate; and an encapsulation layer on the display unit, the encapsulation layer including a plurality of inorganic layers and a plurality of organic layers, the plurality of inorganic layers and the plurality of organic layers being alternately located, and the plurality of organic layers being at a region where the plurality of inorganic layers is located. The plurality of inorganic layers covers the display unit and is sequentially on the substrate, and areas of each of the inorganic layers are increased moving in a direction away from the display unit.