A display apparatus includes a transparent display device, a first polarizer on a first surface of the transparent display device, a first retarder between the first polarizer and the first surface of the transparent display device, a second polarizer on a second surface of the transparent display device opposite the first surface, and a conversion retarder between the second polarizer and the second surface of the transparent display device, the conversion retarder being configured to delay a wavelength of the external light within a range from a first phase to a second phase and to transmit the wavelength-delayed light therethrough when power is supplied to the conversion retarder.