This volume presents the findings of the cooperative religious education project "Christian-Islamic Religious Education in Teamteaching". In this specific teaching setting, one Catholic and one Islamic teacher taught religious education in teamteaching, which was subsequently evaluated by an interreligious research team. The contributions provide multi-layered insights into the framework, conception, implementation and evaluation of the project and show what can be derived from it for the didactics of interreligious school education. The focus is on concrete results from classroom research, the clarification of the learning situations of the students as well as the prerequisites and conditions for the successful cooperation of the teachers.