The overall aim of this chapter is to outline and discuss the use of Jürgen Habermas’ theory in a Nordic participatory research project about values education in early childhood education and care. Two main issues are in the forefront. One issue is of an ontological character and concerns the choice of Habermas’ theory to explore values education. The borrowed concepts, for example, lifeworld and system, are presented and problematized in relation to how they have been applied in the Nordic project. Another issue is of an epistemological and methodological character and refers to the relationship between theory, method and findings when investigating values. The emphasis is on the theoretical impact on data constructions and the conclusions that can possibly be drawn. By highlighting both opportunities and limitations in the use of Habermas’ theory in the research on values education in early childhood education and care (ECEC), this chapter can assist readers in their own research considerations. Another contribution is the theoretical contextualization of the ECEC practice, showing the utility of the theory for understanding a pedagogical practice and also the utility of empirical analyses for developing the theory.