The foreign fighter phenomenon in Syria and Iraq has led to many worries about the potential negative consequences that might occur in the near future. The scenario of returned foreign fighters launching attacks in the West is by far the most prominent one. This article aims to broaden the discussion on the potential fallout of the phenomenon by examining three particular dimensions: the physical threat (including the terrorist threat), ideological consequences, and societal consequences. After presenting these dimensions, three historical cases of jihadi foreign fighting (Afghanistan, Bosnia and Somalia) are examined to see to what extent different types of fallout materialized. The final part of the article attempts to gauge which indicators or signs of potential fallout are already observable in the case of the on-going conflict in Syria and Iraq. If we seek to prepare ourselves for the future fallout of today’s foreign fighter phenomenon, we must look beyond the terrorist threat.