There is a strong need to complement the analysis of social well-being at the European regional level to supplement existing, predominantly economic analysis. This work extends the measurement of well-being across the EU-15 regions in several ways. First, we assess the determinants of well-being using a multilevel modelling approach using data at the national, regional and individual levels. Second, we have extended the model to account for the effects of social interactions within each group, as well as intrinsic socio-demographic indicators and higher-level exogenous contextual factors. Empirical findings support the idea that well-being is strongly dependent both on these general forms of social interactions and on more specific individual characteristics. We find that there is some evidence of greater regional effects relative to national effects, but individual well-being continues to be affected most by micro-level phenomena.