Usually, knowledge spillovers (KS) are related to geographic proximity. In the present study, we measure KS on the basis of different proximity matrices, focusing on the relational, social, cognitive and technological preconditions for knowledge diffusion. In the light of previous studies on KS, we examine: (i) which types of proximity enhance or hamper knowledge flows, and (ii) whether local absorptive capacity favour such flows. Our results indicate that KS across European NUTS2 regions measured through geographic, relational, social, cognitive and technological proximity channels increase with local absorptive capacity. This finding points towards the emergence of large clusters of regions (absorptive capacity clubs) where relational, cognitive, social and technological proximity lock-in maximizes the returns to local investment in R&D.