Backlighting refers to the process of illuminating the subject from the back. In other words, the lighting instrument and the viewer are facing towards each other, with the subject in between. This causes the edges of the subject to glow, while the other areas remain darker. The backlight can be a natural or artificial source of light. When artificial, the back light is usually placed directly behind the subject in a 4-point lighting setup.

A back light, which lights foreground elements from the rear, is not to be confused with a background light, which lights background elements (such as scenery).

In the context of lighting design, The back light is sometimes called hair or shoulder light, because when lighting an actor or an actress, backlighting will cause the edges of his or her hair to glow if he or she has fuzzy hair. This gives an angelic halo type effect around the head. This is often used in order to show that the actor or actress so lit is "good" or "pure". In television this effect is often used in soap operas and has become something of a cliché of the genre. It is also sometimes called the kicker or rim light.