An organic light-emitting diode (OLED) display is disclosed. In one aspect, the OLED display includes a plurality of pixels and each pixel includes a first area configured to emit light and a second area configured to transmit external light therethrough. Each pixel also includes a first electrode formed in the first area and an organic layer formed in the first area and the second area, wherein the organic layer covers the first electrode. Each pixel further includes a second electrode covering at least the organic layer formed in the first area and having a first opening exposing at least a portion of the organic layer formed in the second area. A reflection prevention layer is formed substantially covering the organic layer formed in the second area. The reflection prevention layer has a refractive index lower than that of the organic layer.