Within the central topics of the debate on teachers’ professionalism are the problems of research-based and evidence-based initial and lifelong teacher behavior. Although the statements on professional similarities of teacher actions with those of other (academic) professionals are very plausible, there remains a central task for teacher education How to develop towards such expertise—which is equal to evidence convictions—effectively and efficiently. Which role do scientific research and its results play in this context? How can research results be converted into recommendations for teacher actions?