The aim of this article is to explore how a sociopolitical analysis can contribute to a deeper understanding of critical aspects for becoming primary mathematics teachers' identities during teacher education. The question we ask is the following: How may power relations in university settings affect becoming mathematics teachers' subject positioning? We elaborate on the elusive and interrelated concepts of identity, positioning and power, seen as dynamic and changeable. As these concepts represent three interconnected parts of research analysis in an on-going larger project data from different sources will be used in this illustration. In this paper, we clarify the theoretical stance, ground the concepts historically and strive to connect them to research analysis. In this way, we show that power relations and subject positioning in social settings are critical aspects and need to be taken seriously into account if we aim at understanding becoming teachers' identities.