A display module including a display panel and a backlight module disposed on a side of the display panel is provided. The backlight module includes a light guide, a light emitting diode, and a first optical film. The light emitting diode has a light emitting surface adjacent to the light guide. The first optical film is located between the light guide and the display panel. The first optical film includes a first prisms extending along a first direction. The first prisms has a first unit area and a second unit area. A first part of the first prism in the first unit area has a first average height larger than a second average height of a second part of the first prism in the second unit area.