This PhD thesis investigates the institutional characteristics of state school inspection, set within an international research and policy context. The thesis, coined the NOSI-project (State School Inspection in Norway), is nested within the larger LEXEL-project (Legal Standards and Professional Judgment in Educational Leadership). In the NOSI-project, the main aim is to inquire upon the formation and reformation of the institutional aspects of a system which has not yet been settled, and the enactment of school inspection (SI) as a regulative set of tools which states use in order to govern local authorities and public schools. The main point of focus is the Norwegian example. I first show how educational policy and legal statutes articulate state school inspections in Norway and Sweden. Next, I examine how inspections are perceived and projected by policy actors. Finally, I consider how they are institutionalized in the Norwegian system that is currently shifting, and in which toolsets are being employed. In the Norwegian context, little empirical research has been conducted on how school inspection (SI) represents a major resource in the central state's quest to govern the educational sector within a system that is changing in order to meet new expectations. Tools currently being employed in Norway include circulars, White Papers, and legal statutes (on the policy level), as well as inspection handbooks and, increasingly, School Self Evaluation (SSE) on the practical level. The combination of these tools and how they are administered is shifting in order to include additional methods of evaluating schools and school districts. Norway, in particular, but also Sweden, serve as examples of how policy trajectories evolved in the 2000s and are shaped by the composition of tools and governing modes across contexts. The findings of the NOSI-project are reported on in three research articles viewed through two conceptual lenses that draw on governing literature and new-institutionalist theory. In the first article (Article I), school inspection policy and regulation (2002-2012) in Norway is compared to parallel developments in Sweden through the analysis of 23 policy documents, legal statutes, and regulations. First, the paper demonstrates that even if the cases of public administration appear homogenous from the outside, there is substantial evidence of major differences in the inspection policies of these two countries. Secondly, findings show that in Norway, governing has, until recently, focused on legal and pragmatic approaches to inspection, while in the Swedish case, the emphasis in the same period placed on professional and expert-defined modes in addition to regulation. I am greatly indebted to many people. I would first like to thank the Research Council of Norway for funding the NOSI-project (State School Inspection in Norway). Of course, this thesis would not have been possible without the generosity of my informants and the gatekeepers who opened up the world of Norwegian school inspection to me and my re...