A transparent display device includes a first substrate including a pixel region and a light amount controlling region. An organic light emitting display is positioned in the pixel region and includes an anode electrode, a pixel defined layer, an organic light emitting layer positioned on the anode electrode and in an opening part of the pixel defined layer, and a cathode electrode positioned on the organic light emitting layer. A liquid crystal display is positioned in the light amount controlling region and includes a pixel electrode, a roof layer facing the pixel electrode, and a liquid crystal layer having a plurality of microcavities between the pixel electrode and the roof layer. The microcavities include liquid crystal molecules. A second substrate seals the organic light emitting display and the liquid crystal display.