Critical mathematical literacy empowers all citizens to robustly interrogate their lived experience, and to probe the accuracy of information presented to them. Educators play a central role in empowering children to apply mathematics critically, and this chapter aims to support such valuable work by unpacking theory relating to key components of critical thinking. In addition, the chapter includes a model for critical numeracy that children and teachers can apply to explore scenarios they encounter within and beyond the classroom. In this chapter, we highlight the potential of mathematics education to raise awareness of societal structures, and to contribute to the development of children’s positive social and cultural identities. We draw attention to the role of contexts in exploring mathematical concepts, and how educators have opportunities to prioritise meaningful socio-political contexts over normalisation of capitalism and consumerism. We outline how narratives may be shared with children that broaden their understanding of the global origins of mathematics. The chapter concludes with two lesson-exemplars that adopt a social justice context in order to provide a meaningful opportunity for learners to engage with the tools of critical mathematics literacy.