We examine the effectiveness of accountability systems that rely on patient reporting in Kenyan health clinics. Patients and health care providers from public and private health clinics participate in a lab-in-the field experiment focusing on the relationship of trust between patient and provider. Patients decide whether to trust providers, providers have discretion over their reciprocity, and patients can complain. We compare the effectiveness of: (1) a client reporting system where patients’ complaints are disclosed to the providers’ professional peers, possibly leading to non-monetary penalties, (2) a system where complaints lead to monetary penalties, and (3) a system that, like a standard complaint box, attaches no tangible consequences to complaints. Overall, our findings suggest that citizen reporting systems that leverage peer pressure and reputational concerns can improve service delivery.