The school subject computer science poses special challenges on its teachers (i. e. due to rapid technological changes). Beliefs and motivational orientations play a special role in the context of professional competence, because they influence the teachers classroom behavior and long-term psychological functioning. In this dissertation three studies are conducted to identify, differentiate and analyze the structure of computer science teachers professional beliefs and motivational orientations for the first time, using approaches of psychological competence modeling. In the first study, subject-specific categories of beliefs and motivational orientations are identified and differentiated based on qualitative research methods. The result is a competence framework model which describes the computer science specific beliefs and motivational orientations. In the second study, a qualitative comparison of experts and novice-teachers was conducted. The results show differences in the degree of differentiation with regard to selected beliefs. In the third study, the constructs were tested according to their dimensional structures. The expected structures can be widely confirmed by empirical testing in structural equation models. Overall, the described facets of computer science teachers beliefs and motivational orientations are identified, described and empirically analyzed for the first time using a mixed-method approach.