A liquid crystal display (LCD) device, a luminance difference compensating method thereof, and a method for compensating for a luminance variance in a LCD device are provided. The LCD device comprises a plurality of LCD modules tiled together, each of a plurality of microlenses provided on each of the plurality of LCD modules and including a curved portion and a flat portion, a timing controller for outputting RGB data, and a lookup table for separating the RGB data corresponding to the curved and flat portions of each of the microlenses, for converting the RGB data of the curved portion, and for outputting the RGB data corresponding to the flat portion and the converted RGB data corresponding to the curved portion. Accordingly, luminance differences are reduced or eliminated.