Founded in October 2014, the German far-right activist group PEGIDA saw a rapid rise over only a few months. It subsequently spread to other European countries, most prominently to other German-speaking countries and to Scandinavia. We focus on Austria and Norway, which in contrast to Germany have had strong far-right parties in parliament for over two decades. Combining network analyses of PEGIDA and their opponents’ online activity with a qualitative content analysis, we ask the following questions: how did PEGIDA diffuse from Germany to Austria and Norway? What were the online activities of these groups, how did they relate to other social movement organizations and to established parties? Furthermore, what characterized the online response of the counter-movement against PEGIDA? Finally, how did the established mainstream and far-right parties react? Using this multi-pronged approach, we aim to develop insights into a crucial current episode of anti-Islamic mobilization and the corresponding counter-mobilization.