Supervision is critical to health care because it checks on how health workers actually implement program activities, provides support to them, and holds them accountable for their performance. Supervision systems in developing countries, however, have largely failed to meet these expectations. Efforts to redefine and reorient supervision have not yet succeeded in meeting the challenges posed by low-resource settings. New approaches to health care supervision that promise to be more effective, sustainable, and scalable in developing countries are needed.