Reflective competence is a key component of professional action in teaching situations (Lindmeier et al., 2020). The qualitative study provides insights into the reflective competence of German prospective primary school teachers in mathematics. Video vignettes created by the participants themselves were used for this purpose. These showed videotaped teaching sequences in which the participants instructed a group of primary school children (grades 1 to 4) in self-created open-ended mathematical tasks. In addition, the vignettes show the children’s working processes. In a stimulatedrecall interview based on the participants’ own video vignette, the prospective teachers reflected on their teaching actions as well as the observed learning processes of the children. First results show that prospective teachers address several requirements for reflective competence, such as references to the task, to children’s behaviour, and to their own role as teachers, which are complexly related.