International regulatory agreements depend largely on self-reporting for implementation, yet we know almost nothing about whether or how such mechanisms work. We theorize that self-reporting processes provide information for domestic constituencies, with the potential to create pressure for better compliance. Using original data on state reports submitted to the Committee Against Torture, we demonstrate the influence of this process on the pervasiveness of torture and inhumane treatment. We illustrate the power of self-reporting regimes to mobilize domestic politics through evidence of civil society participation in shadow reporting, media attention, and legislative activity around anti-torture law and practice. This is the first study to evaluate systematically the effects of self-reporting in the context of a treaty regime on human rights outcomes. Since many international agreements rely predominantly on self-reporting, the results have broad significance for compliance with international regulatory regimes globally.