<p>This paper draws on three recent collaborative research projects conducted with teacher researchers in primary and secondary schools in London, UK. All three projects shared a critical participatory action research (CPAR) methodology and a focus on developing pedagogies to address issues of equity in mathematics classrooms. Equity is framed in terms of the entitlement of all learners to a high-quality mathematics education, including access to powerful mathematical knowledge and meaningful learning experiences. The research was informed by Bourdieu’s theory of reproduction which describes the school’s primary function as reproducing inequity from one generation to the next, with school mathematics playing a key role in limiting learning opportunities for students from marginalised groups. The paper argues that teachers need to recognise and confront myths and discourses that permeate school mathematics so that structural causes of inequity can be exposed and challenged. A cross-case synthesis of findings from the three projects identified key design features of the CPAR model that enabled teacher researchers to disrupt common beliefs and assumptions about mathematics teaching. This synthesis demonstrates the potential of the CPAR model to transform teachers’ thinking through critical reflection on existing classroom practice. Through becoming more critically aware of systemic inequities, teacher researchers were able to develop progressive and critical pedagogies that had a positive impact on the mathematical engagement and achievement of students from marginalised groups. Implications for practice are identified which will be of interest to teachers, teacher educators, school leaders and policy makers committed to promoting equitable mathematics teaching.</p>