A display device includes a display panel and a backlight unit which provides light to the display panel. The backlight unit includes a light source which emits the light, a light guide plate which guides the light emitted from the light source toward the display panel, and a prism plate. The prism plate includes a base film disposed on the light guide plate and a plurality of prisms disposed on the base film. Each of the prisms has an isosceles trapezoidal section, two base angles of which are obtuse angles, when viewed from a cross-sectional view in a width direction.