摘要:The aim of this study is to reveal undesired behaviors of secondary school teachers and their effects on students from the students’ point of view. The participants were ninety-six students. The study was designed as a case study, and the data which was obtained though focus group interviews analyzed with content analysis method. According to findings, the undesired behaviors of secondary school teachers were categorized under four themes as ( i ) undesired teacher behaviors related to teaching and learning process, ( ii ) undesired teacher behaviors related to teacher-student interaction, ( iii ) undesired teacher behaviors related to behavior management, and ( iv ) the effects of these behaviors on students. It is concluded that secondary school teachers could show undesired behaviors in the dimensions of teaching-learning process, student-teacher interaction, and behavior management. These behaviors also had negative reflections on students’ willingness to communicate and on their learning.