The caoineag (Scottish Gaelic pronunciation: [ˈkʰɯːɲak]) is a female spirit in Scottish folklore and a type of Highland banshee, her name meaning "weeper". She is normally invisible and foretells death in her clan by lamenting in the night at a waterfall, stream or Loch, or in a glen or on a mountainside. Unlike the related death portent known as the bean nighe, the caoineag cannot be approached or questioned or be made to grant wishes.

The Scottish folklorist Alexander Carmichael in Carmina Gadelica states that she foretells the death of those slain in battle, and that her mourning and weeping cause much anxiety to parents whose sons are in the wars. Before the Massacre of Glencoe, the caoineag of the MacDonalds was heard to wail night after night. Those whose fears were roused by her keening left the glen and escaped the fate of those who remained behind. Fragments of the dirges said to have been sung by the caoineag before the massacre were collected by Carmichael:

Little caoineachag of the sorrow Is pouring the tears of her eyes Weeping and wailing the fate of Clan Donald Alas my grief that ye did not heed her cries

There is gloom and grief in the mount of mist There is weeping and calling in the mount of mist There is death and danger, there is maul and murder There is blood spilling in the mount of mist

Other local names for her include caointeag, caoineachag, caointeachag, and caoidheag.