This article starts with two empirical observations from Organisation for Economic Co-operation and Development countries about longer constitutions: (1) they are more rigid (that is, more difficult to amend) and (2) they are in practice more frequently amended. The study presents models of the frequently adopted rules for constitutional revision (for example, qualified majorities in one or two chambers, referendums) and demonstrates that, if longer constitutions are more frequently revised, it is because they must impose actual harm on overwhelming majorities. In trying to explain this finding, the article demonstrates that longer constitutions tend to contain more substantive restrictions. Countries with longer constitutions also tend to have lower levels of GDP per capita and higher corruption. Finally, the negative effect of constitutional length on GDP per capita is shown to persist even if corruption is controlled for.