This paper reports how metaphor theory was used to explore pre-service mathematics teachers' beliefs about mathematics and the learning and teaching thereof. Furthermore, it outlines how this theory was mobilised to engender self-critique and professional development with these teachers. The core of the paper reports findings from an analysis of the metaphoric content of early course assignments and considers possible pedagogic consequences of the various metaphoric frames. Then I outline, and consider the usefulness of, the process through which these findings were used to provoke critical reflection and discussion around the implications for their work as new teachers of mathematics.