A display device including an optical member, a display panel disposed above the optical member, and a plurality of light emitting units disposed below the optical member and providing a first color light to the optical member. The optical member may include a glass substrate containing an upper surface and a lower surface facing each other in a thickness direction and overlapping the plurality of light emitting units in a plan view, and a quantum dot layer disposed directly on the upper surface or the lower surface and converting the first color light into a second color light and a third color light.