A scanning backlight for a stereoscopic 3D liquid crystal display apparatus includes a light guide formed from a plurality of segments. Each segment has a first side and a second side opposite the first side, and a first surface extending between the first and second sides and a second surface opposite the first surface. The first surface substantially re-directs light and the second surface substantially transmits light. The plurality of segments are arranged substantially in parallel and with the second surfaces transmitting light in substantially the same direction to provide backlighting for a stereoscopic 3D liquid crystal display. A first light source is disposed along the first side of each segment for transmitting light into the light guide from the first side, and a second light source is disposed along the second side of each segment for transmitting light into the light guide from the second side. Each segment first and second light source is selectively turned on and off in a particular pattern and each segment light source selectively transmits light into the light guide first side or light guide second side to form a scanning backlight.