An organic light-emitting display device includes a substrate. A buffer layer is formed on the substrate. A thin film transistor is disposed on the buffer layer. The thin film transistor includes an active layer, a gate electrode, a source electrode, a drain electrode, a first insulating layer, and a second insulating layer. An uneven pattern is formed by patterning the buffer layer. A first pixel electrode is disposed in an opening formed in the second insulating layer. The first pixel electrode includes a transparent conductive oxide. A second pixel electrode is disposed on the first pixel electrode. The second pixel electrode includes a semi-transmissive layer. An organic lighting-emitting layer is formed on the second pixel electrode. An opposite electrode is formed on the organic lighting-emitting layer.