Mobbing practices at schools have been increasing and affecting education process negatively. This study aimed to examine the school principles' mobbing practices against the primary school class teachers and provide suggestions in order to clear away mobbing behaviours. For this purpose, 25 teachers were interviewed face-to-face with a semi-structured interview form in Üsküdar and Ümraniye, Istanbul. The data were analyzed with qualitative research methods and assessed through the content analysis. The results yielded that the school principles' mobbing practices caused uneasiness, enervation, conflict, stress, distrust against the managers, feelings of unworthiness and decrease in motivation, school devotion and performance among class teachers. It was suggested that providing training to principals and teachers about mobbing, setting up psychological consultation centers at schools, generating related legal and pedagogical arrangements might be helpful. [This paper was published in: Kakana, D-M. & Manoli, P. (Eds.) (2017). "Digital Proceedings from the 3rd International Symposium on New Issues on Teacher Education-ISNITE 2015" (Volos, Greece, September 11-13, 2015), p.50-56. Volos: University of Thessaly Press.]