Far too few students enrolled in teacher training specialize in physics. In this research we seek to clarify whether one possible reason is that students hold competence-related stereotypes favoring male, non-immigrant teachers. Physics is strongly associated with maleness and high competence. We predicted that student teachers conceive teachers as less competent for teaching physics if the teacher belongs to a social group that is target of negative performance related stereotypes; i.e., if the teacher is female and has a migration background. In an experimental online study, 144 non-immigrant student teachers read about a teacher’s first day at school. Target teacher’s name (German vs. Turkish) and gender was varied at random between participants. A significant three-way interaction indicated that competence judgments depended on participants’ gender: male and female student teachers perceived female targets as less qualified for teaching physics than men — among males when female targets were Turkish; among females when they were German. Findings were replicated in a sample of 358 non-immigrant students enrolled in various fields of study other than teacher training. Results advise that raising sensitivity towards stereotypic perceptions need to be, even more than it is now, an essential element of the professional development of teachers.