The law of defamation in South Australia is largely governed by the common law, supplemented by the Defamation Act 2005 . The purpose of the law of defamation is to protect a person's reputation (generally by awarding damages), while at the same time protecting the right to freedom of speech.

Defamation actions tend to be time consuming and expensive. Delays in the courts often mean that an action is decided long after the cause of grievance has been forgotten by all but the parties involved. At the end of a case a court can only award monetary damages or an injunction. The court cannot order an apology. Reliving hurtful events is stressful and the emotional trauma of defamation can seldom be cured by the satisfaction of winning a case or from compensation. Litigation should not therefore be commenced without careful thought and expert legal advice.