Science is the major focus of PISA in 2015. Hence this chapter seeks to explore the positive and negative aspects of the PISA assessments. The chapter begins with a description of the new framework used for the science assessment in 2015. This provides an explanation of the changes and possible improvements from the 2006 framework. There then follow three contributions that explore the major social and political impact that PISA is having on education systems, schools and the learning of science going from the global to the local. Beginning with the global, the first argues that PISA should be seen in a political and cultural context, and as an instrument of power in that PISA has led to a global race in education, and is being used to legitimize neoliberal school reforms that are detrimental to the values usually promoted by educators in many countries. The next two contributions are drawn from an exploration of the effects of PISA in one country – Sweden. Taking a systemic view, the first argues that the PISA results provide a much needed external indicator and measure of the performance of the system in any one country showing how educational attainment has declined significantly in comparison to other countries and, in addition, exposing the increasing divergence between high and low performers. Such data provides a useful contrast to internal measures which may offer a different picture. The final contribution draws on a study that has explored how groups of 15-year-old students from an average comprehensive school interpret the PISA items and construct responses. The findings from this work cast doubt on the validity and comparability of the results between countries. The primary goal of this paper is to explore what PISA offers and to raise questions about its value for researchers and educators.