An organic light emitting display device is discussed. The organic light emitting display device according to an embodiment includes an organic light emitting diode layer provided at an active area of a base substrate; an encapsulation layer encapsulating the organic light emitting diode layer to protect the organic light emitting diode layer; an adhesive layer in the encapsulation layer and provided on the organic light emitting diode layer to cover upper and side surfaces of the organic light emitting diode layer; and an encapsulation substrate in the encapsulation layer and provided on the adhesive layer. The encapsulation substrate is provided to have different thicknesses at the active area and outside the active area.