This article describes how sociocultural theories can be used to gain knowledge of why, in international knowledge comparisons such as the PISA, it seems so difficult for Swedish students to answer test questions in scientific literacy “correctly”. Sociocultural concepts (interaction, contexts, cultural tools, social languages, resistance, and situatedness), which I mean can contribute to understanding what might take place in the encounter between students and test items, are discussed and illus trated with two brief examples from an ongoing dissertation project. The article also describes the motive for the chosen research design: to study an encounter between 15 year old students collaboratively working with a few selected PISA items on scientific literacy. Possible consequences of the items being embedded in “everyday contexts” and the significance of mastering a scientific discourse are discussed. Finally I ask which image of science the students are afforded by the test items.