Abstract Cyberhate describes various forms of online communication initiated by hate groups with the purpose of attracting new members, building and strengthening group identity, coordinating group action, distributing propagandistic messages and indoctrination, provoking counterreactions as part of propagandistic campaigns, and attacking societal groups and individuals with hateful messages. A large segment of research under the label “cyberhate” has focused on racist and xenophobic groups (especially white supremacist groups in the United States) and their use of email, websites, blogs, and social online networks. However, the general principles and functions of cyberhate can be identified in the online communication of other extremist groups as well, for instance religious extremists with comparable supremacy, separatist, or extermination ideologies. Typically these groups portray themselves as being oppressed or endangered by a far more powerful, misguided, or despicable enemy, as part of an attempt to justify unrestrained hate and extreme actions.