This article deals with the role of criminal law in dealing with defamatory expressions about religion or belief. Defamation of religion and belief is a form of indirect defamation ‘via identification’ which, as the discussion about the Dutch group defamation law shows, stretches up the notion of ‘group defamation’ — a crime which requires that (groups of) persons are insulted because they belong to a religious group. This contribution investigates whether European states can legitimately criminalise (certain forms of) defamation of religion and belief, in light of the European Convention on Human Rights, the United Nations framework (particularly the International Covenant on Civil and Political Rights) and legal theoretical considerations. The article shows how problematic it is for the criminal law — in light of the rights to freedom of expression and freedom of religion, as well as the ultima ratio principle — to combat such speech.