Teachers make a lot of choices and handle different kinds of didactical dilemmas in their everyday teaching. Research on teaching traditions in classroom practice show that didactical challenges often do not have any clear or obvious solution, but rather needs to be made visible, problematized and discussed by teachers. In this chapter, we illustrate and discuss how comparative didactics as a growing research area may contribute to a deeper understanding of teaching in different subjects. We take our departure in research in the Nordic and French traditions of didactics and describe how research contribute to analyses, critical discussions about and development of teaching and classroom practice. More specifically, we argue that comparative didactics should be seen as a way of dealing with questions about similarities and differences in teachers’ selection of content and manners of teaching and how these selections may influence classroom practice and students’ learning. In the chapter, we focus on, illustrate and discuss two characteristics of comparative didactics. First, one of the overall ambitions of comparative didactics is to analyze what is taken for granted in different educational practices and to identify things not possible to see without doing the comparisons with other practices. Second, the comparisons between educational practices contribute with knowledge of a wide range of alternative ways of selecting goals, content and manners of teaching and can be used in the development of teaching. We focus on these questions with the specific ambition to focus on issues about teaching, classroom practice and educational content.