This article presents a possible framework for the cooperation of mathematics and physics education research domains. Moreover, the potential topics for such a scientific collaboration are explained by means of a structuring qualitative content analysis of current handbooks and conference proceedings in Germany and Vietnam. These topics can form a basis for further projects on the connection of subject-related didactics. One of these projects is an interdisciplinary course in teacher training at the Hanoi National University of Education (HNUE) as part of the Inter TeTra project between the HNUE and the University of Siegen.