Ulcha Dearg ua Caillidhe

Ulcha Dearg ua Caillidhe (fl. 682), known as Redbeard, was a seventh-century Irish assassin.

Ulcha was of the Conmhaícne Cúile Tolad in what is now south County Mayo. In 682, he killed King Cenn Fáelad mac Colgan in Connacht.