A considerable debate precludes drawing conclusions about oil’s effect on democracy. This article challenges this stalemate by significantly expanding the scope of the previous research and using meta-regression analysis to examine the integrated results of extant scholarship. While the results suggest a nontrivial negative association between oil and democracy across the globe, they also indicate a notable variation in this relationship across world regions and institutional contexts. A conditioning effect of institutions may lie more in a broader set of economic and political institutions, less so in previous political regime, but not in institutions associated with British colonial past. Finally, while oil does not seem to impede democracy by retarding two key channels of modernization—income and urbanization—it may have an indirect negative effect on democracy through its adverse impact on education.