In recent years, science, technology, engineering and mathematics (STEM) approaches in education have received growing attention in the political arena and in educational research and practice. A concern consistently raised in the research literature regarding interdisciplinary STEM education is that the role played by mathematics is understated such that it may be overshadowed by the other disciplines. This study contributes to the discussion by presenting a review of 4,812 studies, of which 37 with descriptions of STEM activities were selected, analysed and synthesised to identify the various roles played by mathematics in these STEM activities. This process produced an analytical framework that captures the various roles mathematics can play, which can be categorised into two major categories: mathematics as the specific aim of the activity or mathematics utilised as a tool. Two cases selected from the review are presented in this study to demonstrate how the framework can be employed in analysing STEM activities. Furthermore, we propose using the framework when developing STEM activities as a tool to ensure explicit awareness of the various roles mathematics can play.