In a rapidly changing and challenging world, teachers as influential social agents can play an important and promising role to guide through but also bring about positive change to individuals and society as a whole. This potential stresses the importance of professionalization of teachers and the need for elaborate learning settings to equip (future) teachers as psychologically literate and reflective practitioners who systematically reflect and integrate practice and (psychological) theory. As part of the preservice teachers' psychology curriculum, we implemented a theory-practice learning setting in their educational foundation studies that aims at fostering preservice teachers' psychological literacy. Specifically, to reflect their own and other's behavior and to apply their psychological knowledge of learning and counseling principles into real-life counseling sessions. This study addresses the didactical concept of teaching psychology to non-psychology students and the results from its evaluation. In a quasi-experimental pre-posttest design with comparison group (N[subscript intervention] = 46; N[subscript comparison] = 102), we analyzed the effects of the seminar on the preservice teachers' reflexivity, their beliefs about the theory--practice relationship and their agency. Results indicate that beliefs about the theory--practice relationship and the levels of reflection significantly increase through the practice task in the intervention group, but reflexivity and agency does not.