Research in science education identified a variety of attitudes and beliefs that shape and/or are shaped by classroom experience. The present study identified high school teachers' beliefs about Physics and learning Physics. Since the background of the forty-one teachers who participated in a six-week in-service training program was neither in Physics nor in Physics education, the training program was designed to upgrade their conceptual understanding of Physics, and their skills and competencies in teaching Physics. Using the profile obtained from the Colorado Learning Attitudes about Science Survey (CLASS) and the grades that the participants obtained in the various courses they took, the relationship between teachers' beliefs and their grade point average is presented. Implications for classroom practices are also discussed.