A backlight module including a light guide plate, a plurality of point light sources and a frame is provided. The light guide plate includes a body, a positioning structure and a plurality of first micro-structures. The body has at least one light incident surface, an upper surface connected with the light incident surface, and at least one side surface connected with the light incident surface and the upper surface. The positioning structure is located on the side surface, wherein the upper surface has a first eliminating region adjacent to and surrounding the positioning structure. The first micro-structures are arranged on the upper surface except the first eliminating region. The point light sources face the light incident surface. The light guide plate is positioned in the frame by matching the positioning structure with a positioning component of the frame. A display device including the backlight module aforementioned is also provided.