This doctoral thesis comprises two questionnaire studies and two small-scale interview studies on the content and structure of physics teachers__ belief systems. The studies focused on teachers__... Show moreThis doctoral thesis comprises two questionnaire studies and two small-scale interview studies on the content and structure of physics teachers__ belief systems. The studies focused on teachers__ beliefs about the goals and pedagogy of teaching and learning physics, and the nature of science. The samples consisted of physics teachers working at secondary schools in the Netherlands (students aged 12-18). The questionnaire studies showed that, on average, teachers__ belief systems about teaching and learning physics were composed of interrelated beliefs about the goals of physics education and more or less distinct beliefs about teacher-regulated learning, student-regulated learning and knowledge construction, and the nature of science. The interview studies showed that teachers differed in their priorities concerning the goals of physics education, as well as the extent to which their beliefs about the pedagogy of teaching and learning physics reflect student-regulated learning. No clear relationship was found between beliefs about the nature of science and beliefs about the goals and pedagogy of physics education. The main conclusions are discussed by paying attention to theoretical perspectives such as pedagogical content knowledge (PCK) and practical knowledge. The practical implications for teacher education and professional development emphasize the importance of building an explicit professional rationale. Show less