Compared to other world regions, the Middle East is exceptional in its resistance to democratization. Whereas a cultural explanation for this democracy gap refers to historical legacies, especially to the dominant role of Islam, an economic explanation emphasizes oil wealth as the main barrier to democracy. According to various quantitative studies, both claims seem to be valid. Nevertheless, none of the explanations is uncontested, as there are always examples that demonstrate the opposite. This paper argues that it is exactly the combination of culture and economic structure that makes democracy in the Middle East unlikely. Both factors mutually reinforce each other on the macro, meso and micro level and thus constitute a cultural-economic syndrome with a strong negative impact on democratic performance. Regression analyses demonstrate the significance of this interaction effect: If the cultural-economic syndrome of Islam and oil wealth is present in a country, its negative impact on democratic performance becomes even stronger than the sum of the additive effects of Islam and oil wealth.