Teaching simulations and mathematical modelling with digital tools requires theory-related pedagogical content knowledge. This type of knowledge consists of theories about the corresponding potentials and possible uses of digital tools and – as meta-knowledge about processing steps – also modelling cycles. These can be used, for example, in the processing of more complex reality-related problems. The article conceptualises this dimension of pedagogical content knowledge and describes a course for pre-service mathematics teachers at the University of Münster and the University of Würzburg, designed to promote this dimension of knowledge, amongst others. Using an intervention study in a pretest-posttest design, it is quantitatively (N = 146) shown that this knowledge can be effectively developed within the treatment.