Abstract. This article presents a new model for explaining the emergence of the party family of extreme right-wing populist parties in Western Europe. As the old master frame of the extreme right was rendered impotent by the outcome of the Second World War, it took the innovation of a new, potent master frame before the extreme right was able to break electoral marginalization. Such a master frame – combining ethnonationalist xenophobia, based on the doctrine of ethnopluralism, with anti-political-establishment populism – evolved in the 1970s, and was made known as a successful frame in connection with the electoral breakthrough of the French Front National in 1984. This event started a process of cross-national diffusion, where embryonic extreme right-wing groups and networks elsewhere adopted the new frame. Hence, the emergence of similar parties, clustered in time (i.e., the birth of a new party family) had less to do with structural factors influencing different political systems in similar ways as with cross-national diffusion of frames. The innovation and diffusion of the new master frame was a necessary, but not a sufficient, condition for the emergence of extreme right-wing populist parties. In order to complete the model, a short list of different political opportunity structures is added.