Cults are negatively regarded. The way in which they persuade people to join their movements is particularly criticised by, for example, the anti-cult movement. Cults do use language in specific ways to recruit new members. There are, however, other groups who use language similarly, for recruitment purposes, but without stigmatisation. A new framework for rhetorical analysis, incorporating both classical tradition and contemporary work in text analysis, is particularly useful at demonstrating this. This thesis develops such a framework and uses it to analyse the rhetoric of three cults, Scientology, The Jehovah's Witnesses and the Children of God, showing that cults' distinctive negative profile in society is not matched by a linguistic typology. Indeed, this negative profile seems to rest on the semantics and application of the term 'cult' itself. Not only does this analysis increase our understanding of rhetoric, it paves the way for new questions to be asked about the pejoration of cults.