Legal discussions of defamation commonly focus on defamation law, with relative neglect of struggles that take place over defamation matters. To understand defamation struggles, we introduce backfire theory: if something is perceived as unjust and information about it is communicated to relevant audiences, it has the potential to backfire against those held responsible. Defamation suits have the potential to backfire when they are seen as oppressive or contrary to free speech. There are several types of actions by plaintiffs that can inhibit this backfire effect, including cover-up, devaluation of the defendant, reinterpretation and intimidation. To illustrate the value of backfire analysis of defamation struggles, we examine four Australian examples, involving author Avon Lovell, politician Robert Askin, solicitor John Marsden and Aboriginal leader Geoff Clark, and the British example of McDonalds suit against two activists. Participants in these struggles see the matters in terms of reputation and free speech; backfire analysis allows an observer to put tactics used by participants in a coherent framework.