Skills in science, technology, engineering and mathematics (STEM) are promoted by the Australian government as pivotal for Australia’s economic prosperity. Research on equity groups suggests that group membership is associated with several factors linked to ‘leakage’ from the STEM pipeline of school, university and transition to work. In this paper we draw on longitudinal Australian data to understand what factors influence the participation of equity group students in university STEM courses, and to explore how the STEM pathways of those groups differ from those of non-equity students. We identified several important factors which influence participation at two critical points of the STEM pipeline; transition from school into university, and transition from university into the STEM workforce. Our results indicated that higher levels of mathematics self-concept and instrumental valuing of mathematics in early adolescence predict continuation in the STEM pathway for all students and particularly those from low socioeconomic status backgrounds.