Purpose: This research was carried out to determine the classroom management competency and the levels of perception of understanding of discipline among preschool teachers, the effect of their classroom management competency and understanding of discipline on child-teacher relationship, the relationship between interpersonal problem-solving and liking of children, the student-teacher relationship and the predictive power of interpersonal problem-solving and liking of children in teachers' classroom management competency and understanding of discipline. Research Methods: The research was designed using single and correlational survey designs and the sample included 180 preschool teachers working at public and private preschools. Research data was collected using the "Scale of Classroom Management Competency Levels", "Teacher's Understanding of Discipline Scale", "Interpersonal Problem-Solving Inventory", "Barnett Liking of Children Scale" and "Teacher-Student Relationship Scale". Findings: The results revealed that 81% of the teachers need to be supported in terms of classroom management and 55% of them in terms of understanding of discipline. The results showed that professional seniority, negative attitude towards problems and liking of children are the variables that predict strict/over-controlling understanding of discipline, and the constructive problem solving and the discipline based on understanding of equity are the variables that predict their classroom management competency. Implications for Research and Practice: Teachers' development about interpersonal problem-solving skills must be supported as well as their pedagogical knowledge about classroom management. It is suggested that teachers' classroom management competencies should be increased and their understanding of discipline should be developed via education seminars.