This chapter explores teaching repertoires and student perceptions of knowledge in the subjects of natural sciences and Swedish through an analysis of classroom observations, teacher interviews and interviews with 14- to 15-year-old students in high- and low-performance classrooms. There were substantial differences in the dominating teaching repertoires in each classroom, which is explained by social, cultural and relational dimensions concerning teacher–student interactions and student motivations and attitudes towards school in each class. To some extent, the different contextual features of the two classrooms influenced the students’ conceptions of knowledge, but in general, the students shared a common understanding of knowledge as being theoretical, abstract and hierarchically structured, and practical in terms of creativity and developing problem-solving, cooperation, critical thinking and communication skills; a few examples of experiential knowledge conceptions are presented. While the knowledge requirements of the curriculum shape students’ understanding of knowledge, they also consider the value of knowledge as it relates to their future adult and professional life. Based on the analysis, this chapter concludes that classroom dynamics created by situational, contextual, social and cultural factors influence the manner in which student access to knowledge is enabled or restrained.