This paper develops comparisons between Western and Islamic constitutionalism. In Western tradition, the term constitutionalism points to the limitation of government through law. Different models of constitutionalism, in particular the American and French, can be understood in light of the two interpretive categories of constitutional democracy and legislative democracy, respectively. Developments in contemporary constitutionalism appear very complex, as today's constitutions are the reflection of the cultural, religious, social and political pluralism of contemporary societies. Therefore, interpretation, the complexity of which derives from the fact that pluralistic constitutions merge legal issues and moral issues together, becomes central. With regard to Islamic constitutionalism, some Islamic thinkers consider secularism is one  type of philosophy while Islam another type, which has its own vision of human life, rights and duties. From this perspective it follows that it is reasonable to believe that constitutionalism can be achieved differently in different societies depending on the conceptions of rights and duties that are accepted and shared.