Ligidium hypnorum is a species of woodlouse found across Europe and western Asia. It is a fast-moving, active species which rarely grows longer than 9 millimetres (0.35 in). It is dark and shiny, and is similar in appearance to the common species Philoscia muscorum, and also the rarer Oritoniscus flavus. In Great Britain, it was first discovered at Copthorne Common, Surrey in 1873, and the majority of later records are also from South East England. It is considered a good indicator species for ancient woodland.