Over the past 15 years, the assessment of the Programme for International Student Assessment (PISA), which is sponsored by the Organisation for Economic Co-operation and Development (OECD), has become a strategically important actor in international education. This chapter aims to demonstrate how the OECD, and particularly the PISA, has influenced assessment policies and school governing in Norway. First, I examine the key functions of international and national assessment policies. Second, I explore the ways of which the use of national test results is included in local quality assessment systems and how superintendents, principals and teachers perceive the use of these results. Based on this, I will discuss the functions of national achievement tests, how comparison and benchmarking are integrated in school governing and the possible consequences for accountability practices in which visibility creates pressure on key actors in the school system.