A flexible organic light emitting device including a flexible substrate having an active area and a pad area; an organic light emitting diode layer disposed on the active area; an adhesive layer disposed on the organic light emitting diode layer; an encapsulation substrate disposed on the adhesive layer; a cover layer disposed between the active area and the pad area; and a back film disposed on a lower surface of the flexible substrate, further the encapsulation substrate has a curved upper surface outside the active area, also the cover layer decreases in thickness from the active area toward the pad area.