The black-naped monarch or black-naped blue flycatcher (Hypothymis azurea) is a slim and agile passerine bird belonging to the family of monarch flycatchers. They are sexually dimorphic with males having a distinctive black patch on the back of the head and a narrow black half collar ("necklace") while the female is duller and lacks the black markings. They have a call that is similar to that of the Asian paradise flycatcher and in tropical forest habitats pairs may join mixed-species foraging flocks. Populations differ slightly in plumage colour and sizes.