An organic light emitting display device includes: a curved organic light emitting display panel. The organic light emitting display panel includes a flexible substrate, a thin film transistor layer including a semiconductor layer, and an organic light emission layer including an organic light emitting material. In the curved organic light emitting display panel, the thin film transistor layer receives a compressive stress, or a neutral plane in which the compressive stress and a tensile stress maintain equilibrium is defined in the thin film transistor layer.