A subclass of the intermediate-mass, pre-main-sequence Herbig Ae/Be stars; also known as UXors. The light curves show distinctive Algol-like fadings of 1 mag. on a period of days to weeks. These random fadings are accompanied by changes of colour during minima and have been interpreted as due to non-uniform dust structure around the star. UX Orionis itself varies between about magnitude 9.5 and 12.5.