Elcysma westwoodi (often spelled Elcysma westwoodii), commonly known as the white-tailed zygaenid moth, is a species of moth in the burnet moth family Zygaenidae. It has a Palaearctic distribution, being found in Japan, the Korean Peninsula, China, and the Russian Far East. The species was first described by Samuel Constantinus Snellen van Vollenhoven in 1863 as Agalope westwoodii.