This Element advances an agency-theoretic approach to public administration through comparative analysis of the United States, China, and EU. It examines how principals such as legislatures, executives, or ruling parties can align the actions of diverse agents, including civil servants, public agencies, street-level bureaucrats, and contractors, with the public interest. Drawing on an extensive review of 146 key studies and AI-assisted analysis of 8,400 articles from Public Administration Review, Part I outlines fundamental concepts: goal divergence, moral hazard, adverse selection, and information asymmetry and traces its history, debates, and criticisms. These concepts are then applied to key themes in public administration performance management, federalism/decentralization, contracting, politics-administration, and institutional drift. Part II investigates how these problems manifest and tackled in the US, China, and Europe. Part III concludes with a synthesize of findings, debates, extensions, and future directions for theory and practice.
