A display device including a first substrate, a pixel disposed on the first substrate and including first, second and third sub-pixel electrodes adjacent to each other, a second substrate spaced from the first substrate, a color conversion layer disposed on the second substrate and with a first wavelength conversion layer overlapping with the first sub pixel electrode and a second wavelength conversion layer overlapping with the second sub pixel electrode, a transmissive layer including a first sub-transmissive layer overlapping with the third sub-pixel electrode and a second sub-transmissive layer disposed between the first wavelength conversion layer and the second wavelength conversion layer, and a planarization layer disposed on the color conversion layer and the transmissive layer. Methods of manufacturing display devices having a flatter, planarization layer with reduced variations in thickness also is disclosed.