A display apparatus includes: a display panel having a display surface; a light-guiding plate over the display surface, the light-guiding plate including a bottom surface facing the display surface; a light source on a side surface of the light-guiding plate; and a low-refractive-index medium layer between the bottom surface and the display surface, a refractive index of the low-refractive-index medium layer being lower than a refractive index of the light-guiding plate by at least about 0.15.