Despite institutional commitments and concerted efforts towards gender equality, women continue to be underrepresented in full professorships and leadership positions in universities and research organisations. This is particularly evident in the male-dominated field of STEM (Science, Technology, Engineering, and Mathematics). In this thought-provoking talk, Claudia Schredl examines the crucial role of informal institutions (i.e. taken-for-granted gender norms and practices) in shaping power structures in STEM universities.