This paper analyzes the impact of corporate taxation on a firm’s debt policy. We contribute to the existing literature in two ways: (i) we explicitly model persistence in the debt-to-asset ratio, and (ii) we incorporate firm heterogeneity with respect to firm size and legal form. Empirically, this implies the use of dynamic panel data econometrics.We employ a panel of about 110,000 firms from 22 countries of the European Union between 1999 and 2007. First, we find that capital structures exhibit a substantial degree of persistence over time. Second, and in line with theoretical expectations, we find that the debt ratio is positively affected by the statutory corporate income tax rate. Specifically, we observe a marginal effect of around 0.3 in our baseline specification, translating into a short-run (long-run) elasticity of about 0.2 (0.3-1.5). Finally, our empirical results show that large firms react more sensitively to the incentives of corporate taxation, while this effect is smaller for public limited companies.