A light guiding plate capable of minimizing a thickness of a backlight assembly and an LCD device, a backlight assembly and an LCD device having the same are provided. The light guiding plate has a light incident surface, a light reflection surface having a plurality of dots for diffusing and reflecting the light emitted from the light incident surface and a light output surface having a predetermined roughness and further diffusing the light diffused and reflected by the light reflection surface. Thus, a conventional diffusion sheet disposed above the light guiding plate may be removed.