Government accountability is severely lacking in many developing countries, yet we know relatively little about the causal dynamics that produce citizen demands for greater responsiveness. We argue that a sense of ownership over public money heightens expectations for government services and induces expressive demands for accountability, and we apply the new theory in sub-Saharan Africa. Results from a series of lab-in-the-field experiments in Uganda and Ghana and from a nationally representative survey-based field experiment in Uganda all demonstrate that higher feelings of ownership over public revenues significantly increase citizens’ accountability pressures on leaders. Furthermore, simple interventions can significantly increase feelings of revenue ownership over oil and aid windfalls, producing demands for accountability indistinguishable from taxes.