International constitutionalism comes in many different forms. A distinction may be made between those claiming that we today have an international constitution and others arguing that what is of importance is to apply constitutional thinking to the international legal system. The article discusses whether we have an international constitution and concludes with a negative answer. This means that we still must operate with different international legal regimes and with the distinction between the international and national legal systems, i.e. aspects of pluralism. However, the challenge is how to secure constitutional guarantees in a pluralist legal order.