One-stop service shops (OSSs) for government services delivery have become a popular and flexible mode of administrative decentralization for delivering government services of various types throughout the world. Using an analytical framework derived from decentralization, this article examines their introduction in Mongolia paying particular attention to politics, political economy and governance. The Mongolian OSSs have been justified mainly on managerial and governance grounds and are viewed by government as a most successful public administration reform. This article reviews these rationales in the course of tracing the history of the introduction of OSSs into Mongolia. The reform is also located in the political economy of Mongolia using problem tree analysis to evaluate its relevance to the countryâ¿¿s leading development issues. Further problem tree analysis is applied to one of these issues, service delivery. The OSS experiment is also examined through the lens of political analysis paying particular attention to the policy making and policy implementation. The overall picture is one of both success and failure; success in terms of establishing OSSs across Mongolia but failure in terms of the lack of change to bureaucratic processes and the centralization of the State.