Inclusive education aims to provide learning progress for all. It requires assessments to identify learning levels and progress and to adapt and evaluate instruction. We extend the classroom-based assessment (CBA) approach and argue that CBA in inclusive schools consists of the four dimensions of Instructional Decision-Making, Educational Assessment, Identification of Students with Special Educational Needs, and Progress Monitoring. For this paper, we developed both a framework of CBA for research interests and individual scales for each dimension (6 to 9 items per scale) in order to identify the four dimensions in which teachers need further training. To create a more manageable instrument for education and training practice, we tested a combined model as a questionnaire. In a survey of 110 teachers and 152 pre-service special education teachers (N = 252), the individual scales had good internal consistency (α = .92, .82, .92, .93). Using Confirmatory Factor Analysis, an initial combined model, consisting of the revised individual scales, showed acceptable fit values (CFI = 0.94, TLI = 0.89, RMSEA = 0.07, SRMR = 0.06) almost everywhere. The further development of the questionnaire and its significance and relevance for inclusive educational practice will be discussed.