The literature on the Muslim world has found that although Muslims have a high support for democracy, that same support has been lower when it comes to democratic virtues such as tolerance. It has been unclear, however, what specifically about the Muslim world that contributes to this paradox. I offer methodological and theoretical contributions to this scholarly discussion. Methodologically, I employ Bayesian item response theory (IRT) that improves the previous studies by relaxing the requirement that all units of analysis answer an identical set of questions. I present a picture of conservatism levels in 26 countries and offer an insight on the relative importance of social issues among Muslims across the world. On the theoretical level, I provide evidence that it is Islamic conservatism that leads to the tolerance deficit. This conservatism is related to the perception of Islam superiority and different from being pious or traditional.