This work deals with key competency requirements for teachers in inclusive schools. Previously formulated standards and recommendations (Europäische Agentur für Entwicklungen in der Sonderpädagogischen Förderung, 2012; HRK & KMK, 2015) provide specifications that have to be made operationable for the teaching context. In order to be able to develop relevant key competencies, the question investigated was how the key competencies, which have been formulated as relevant for the school context, must be supplemented for inclusive contexts. For this purpose, the term inclusion was compared with existing discourses. Special interviews were analyzed with the help of the Grounded theory methodology. As a core category for learning in inclusive schools, the result is the training of a „situational-flexible normality spectrum“. Based on a medium-range theory, this spectrum forms the reference and frame of interpretation for already formulated standards and recommendations. The knowledge gain is related to the extension or modification of existing models for key competencies around the "situational-flexible normality spectrum" as a reference framework for key competencies in inclusive schools. Practical implications arise for the professionalization by the fact that due to and with the help of the „situational-flexible normality spectrum“ of the relevant key competencies, students can already be sensitised and further developed at university. For further training of already active teachers, the promotion of „situational-flexible normality spectrum“ can be a starting point to perceive and implement diversity as an opportunity.