The Rentier State Hypothesis states that taxation promotes government accountability. The argument is that citizens demand more accountability for spending of tax revenue than for spending of windfall revenue (e.g., natural resource revenue and aid). This paper presents causal evidence from a novel between-subject experiment that tests the effect of taxation on demand for accountability. To investigate the underlying mechanisms of the effect, the design focuses on two main features that distinguish tax from windfall revenue: Tax revenue is produced by citizens' work and has been in their possession before being collected as tax. Consistent with the Rentier State Hypothesis, the main finding is that taxation causes a higher demand for accountability when both features of taxation are present. The paper thus sheds light on the political economy of government revenues, and more generally contributes to our understanding of how features of the tax system shape behavior.