A display device includes: a display panel which displays an image; a light source unit which provides light to the display panel; and a light source controller which transmits a control signal to the light source unit, wherein the light source unit includes a light source including a plurality of light emission blocks, the light source controller includes a first reference determining unit which determines first references based on an input image signal, a reference difference calculator which calculates at least one reference difference for neighboring light emission blocks by using first references, a parameter generator which generates at least one parameter by using the at least one reference difference, and a second reference determining unit which determines a second reference for a corresponding light emission block by using the first references and the at least one parameter.