An organic light-emitting display device includes a substrate, a display unit on the substrate, and a thin film encapsulation unit configured to encapsulate the display unit, and including a corrugated portion including a first layer and a second layer that are sequentially stacked, wherein the first layer includes a material having a lower modulus of elasticity than the second layer, and wherein a corrugated surface is formed at an upper surface of the first layer and a lower surface of the second layer due to a difference in the moduli of elasticity of the first layer and the second layer.