It is a common notion in the historiography of Nordic fascism that antisemitism only became a prominent feature in the mid-1930s under the influence of Nazi Germany. This chapter challenges this perception by examining the ideas and activities of antisemitic parties and propagandists in Norway, Denmark, Sweden, and Finland from the 1920s and early 1930s. These antisemitic propagandists were among the earliest promoters of fascism in the Nordic countries and among the founders of the first movements, years before the Third Reich was established. However, their relations with the fascist organisations they helped launch soon became strained and, for some, rather short-lived, as the earlier parties gradually became a liability to the later movements. Their role as fascist pioneers, as well as their uneasy relationship with the movements they co-founded, is explained by the concept of conspiracism. Applying the concept to studies of antisemitism enables a theoretical distinction between racism and conspiracism, both relating to fantasies, yet distinctively different in terms of argumentative logic and feasible integration in ideological systems such as – but not limited to –fascism.