The Kingdom of Saudi Arabia is blessed with abundant solar energy, which is renewable, clean, and freely available. This paper describes the status of the major research, development, and demonstration (RD & D) activities and achievements at the Energy Research Institute, King Abdulaziz City for Science and Technology, in the field of solar energy. RD & D activities in the Kingdom have confirmed that solar energy has a multitude of practical uses. These include lighting, cooling, cooking, water heating, crop fruit drying, water desalination, operating irrigation pumps, and meteorological stations, and providing road and tunnel lighting. Furthermore, these solar energy RD & D activities and achievements played a significant role in transfer ring technology and manpower development in the Kingdom.