A backlight unit may include a light source, a light guide plate configured to guide light emitted from the light source, a light conversion layer on the light guide plate, and a reflective pattern layer between the light guide plate and the light conversion layer, the reflective pattern layer including a plurality of holes. The light conversion layer absorbs at least a portion of the light emitted from the light source at the first predetermined wavelength and generates light having a second predetermined wavelength different than the first predetermined wavelength. A reflective layer may reflect the light having the second predetermined wavelength toward a display panel.