Provided are a light guide film, a backlight unit, and a display device. Light guide portions are disposed in holes of a reflection plate on which light sources are disposed, and a light guide film is directly disposed on the reflection plate and the light guide portions to provide a light guiding function and a light shielding function. Therefore, a method of facilitating implementation of a backlight unit with a small thickness, which satisfies image quality is provided. Further, each of the light shielding patterns has different reflectances in different areas, thereby increasing the amount of light supplied to an area between light sources. Therefore, a backlight unit with a reduced number of light sources and improved image quality may be provided.