This article empirically analyses regional convergence between Spanish and Portuguese NUTS-3 regions during the period 2000-2015, considering the spatial dependence between these units and the role of educational attainment in this process. After some considerations regarding the model to be estimated, exploratory spatial data analysis (ESDA) is applied to detect two regional clusters grouped by regional product per inhabitant: high-income regions (located in the north-eastern third of the Iberian Peninsula) and low-income regions. For both clusters, various models of educational attainment are examined. These models reveal the presence of regional convergence, and enable us to detect the spatial spillovers that drive this process, which differ between the two clusters. In particular, we observe the influence of tertiary education on the reinforcement of income convergence within the high-income cluster, while for the low-income cluster this role is largely played by secondary education, but in the opposite direction.