In folklore, a werewolf, or occasionally lycanthrope is an individual who can shape-shift into a wolf, either purposely or after being placed under a curse or affliction, with the transformations occurring on the night of a full moon. Early sources for belief in this ability or affliction, called lycanthropy, are Petronius (27–66) and Gervase of Tilbury (1150–1228).

Werewolf witch trials were witch trials combined with werewolf trials. Belief in werewolves developed parallel to the belief in European witches, in the course of the Late Middle Ages and the Early Modern period. Like the witchcraft trials as a whole, the trial of supposed werewolves emerged in what is now Switzerland during the Valais witch trials in the early 15th century and spread throughout Europe in the 16th, peaking in the 17th and subsiding by the 18th century. The persecution of werewolves and the associated folklore is an integral part of the "witch-hunt" phenomenon, albeit a marginal one, accusations of lycanthropy involved in only a small fraction of witchcraft trials.