Unaussprechlichen Kulten (German: "Unnameable Cults") is a fictional occult text created by Robert E. Howard, attributed to the German scholar Friedrich Wilhelm von Junzt, who compiled accounts of secret cults and forbidden gods. Von Junzt died under mysterious circumstances shortly after completing it.
Originally appearing in Howard's own stories, the volume was quickly adopted by Lovecraft and other Mythos contributors, cementing its place alongside the Necronomicon.