An organic light emitting display (OLED) device includes a substrate having a display region including a plurality of sub-pixel regions, a respective driving transistor and a respective switching transistor on the substrate in each of the sub-pixel regions, an insulation layer structure on the substrate, the insulation layer structure having a respective trench surrounding the driving transistor in each of the sub-pixel regions, and a respective sub-pixel structure on the insulation layer structure in each of the sub-pixel regions.