The purpose of this study is to assess in-class behaviors of German language teachers working at Anatolian High schools in terms of social and methodological aspects, and to discuss both the positive and negative effects of these behaviors over the learning environment. Research universe includes the teachers working at Anatolian High schools during the academic year of 2010 and 2011. Whereas a questionnaire was employed in order for teachers to evaluate themselves in terms of professional skills, interview and observation techniques were utilized in order to determine teachers' professional problems and in-class behaviors respectively. Therefore, both qualitative and quantitative techniques were used. Because findings have revealed that teachers can actively use the body language, encourage student participation, are tolerant and flexible with their students, make use of modern techniques during class management, include activities that promote autonomous learning, and have inter-cultural conscious, they are well aware of the importance of teachers' in-class behaviors. However, teachers have also been weak in building a warm classroom environment, in noticing the differences among students' learning abilities, and in becoming an advisor in the classroom. The research outputs have been presented to the educational institutions with advices in terms of the results of this study.