Electoral rules and form of government have important economic effects, for example on taxation and public spending. However, there are no robust results in the literature when it comes to their effect on economic growth. This paper investigates whether electoral rules and form of government affects economic growth by applying panel data techniques on a very extensive dataset. There is no robust effect of presidentialism or parliamentarism on growth. However, there is very robust evidence for a positive, and quite substantial, effect of Proportional Representation (PR) electoral rules on economic growth. This is partly due to PR systems’ propensity to generate broad-interest policies, like universal education spending, property rights protection and free-trade, rather than special interest economic policies. Also semi-proportional systems seem to enhance growth relative to plural-majoritarian systems.