A light guide plate includes a light incident surface to which light is incident as incident light, an opposite surface formed opposite to the light incident surface, a light emitting surface through which the incident light is emitted, a rear surface formed opposite to the light emitting surface and including a prism pattern which reflects the incident light to the light emitting surface, and lateral surfaces, wherein a diffuse reflection pattern is formed on at least any one of the light emitting surface and the lateral surfaces to diffuse-reflect light incident to the lateral surfaces, thus rendering a brightness at both the opposite surface and the light incident surface substantially uniform.