Lighting systems are a costly energy consumer in most facilities, but their energy cost is often overlooked or underestimated. Typical lighting systems are installed for human comfort, safety, and quality, and have a major impact on the operation of the facility as well as on the process equipment. In some types of manufacturing facilities, the annual energy costs for lighting can be as much as 15–20% of the total annual energy spent. Lighting types include incandescent,fluorescent, induction, light-emitting diode (LED), metal halide, sodium, and many more. The intent of this chapter is to focus on typical lighting systems—indoor and outdoor—used in a facility, including the office areas, and to identify some basic energy-saving opportunities.