Terry Pratchett's witches - Granny Weatherwax, Nanny Ogg and Magrat Garlick - are more than just a marvelous spoof of those in Shakespeare's 'Macbeth'. In addition to their undoubted comedic value, they are also a voice for some of the major themes of the Discworld novels. Through readings of extracts from the relevant novels, as well as reference to some modern scholarship, we will examine the differences between witch magic and wizard magic; the role of witches in Discworld society; Pratchett's representations of gender; themes of power and authority, and the presentation of the minor witch characters. Access to the listed texts is desirable. Prior knowledge of at least the majority of the listed texts will be assumed.