Teachers make a difference for the outcome of their students in science classrooms. One focus in this context lies on teachers' professional knowledge. We describe this knowledge according to three domains, namely (1) content knowledge (CK), (2) pedagogical content knowledge (PCK), and (3) curricular knowledge (CuK). We hypothesise a positive relationship between these three domains and students' performance in science. Students' science performance was conceptualised by "system thinking" performance in the context of biology teaching. In order to test our hypothesis, we examined the relationship between the knowledge triplet CK, PCK, and CuK and students' performance. 48 biology teachers and their students (N = 1036) participated in this study. Teachers' content-related professional knowledge and students' performance were measured by paper-and-pencil tests. Moreover, we used concept maps to further assess students' performance. By specifying doubly latent models, we found a significant positive relationship between biology teachers' PCK and students' performance. On the contrary, the results reveal no relationship between CK and CuK and students' performance. These findings are discussed in respect to modelling the interrelationship of teachers' content-related professional knowledge and students' learning in science, as well as concerning their relevance for further research and teacher education programmes.