Relatedness, external linkages and regional innovation in Europe. Regional Studies. This paper analyses if the generation of new knowledge benefits from the combination of similar or dissimilar pieces of existing technologies, in terms of their technological content (related versus unrelated variety), for the case of European regions. Specifically, it analyses the relevance of variety in the case of local knowledge as well as in the case of the knowledge coming from other regions. At the local level, it shows that while related variety is conducive to regional innovation, unrelated variety does play a role, too, when it comes to radical innovations. Conversely, it also shows that external knowledge flows have a higher impact, the higher the similarity between these flows and the extant local knowledge base.