This study aiming to determine the managerial characteristics of the school principals and to reveal the effects on the development of the students was planned in a qualitative case study model. The study group was 16 undergraduate students. The semi-structured letters were used as a means of collecting data in this study written by undergraduate students to the school principals. The findings were analyzed by using content analysis technique. The findings show that school principals exhibit both positive and negative personal characteristics. The most frequent positive personal characteristics of the school principals were good-humored, neat, sympathetic, fair, tolerant, and respectful. The most frequent negative personal characteristics were authoritarian, punitive, normative, strict, and distant attitudes. The school principals exhibit positive administrative features such as to display solution-focused management, to create positive school culture, to make staff feel valuable, and to listen everybody as carefully as. School principals also exhibit negative administrative characteristics such as punitive attitude, extreme restrictive attitude, a distant attitude, and to behave official. The most frequent instructional leadership characteristics of school principals were to focus on educational success of the school, to motivate to learn, to care all students to establish an effective learning environment, to lead to teaching and to appreciate success of students. The positive attitudes of school principals ensure the feelings on students such as self-confidence, self-respect, feel precious, gratitude, awareness, love and courage. The negative attitudes ensure the feelings such as fear, violence, humiliation, lack of self-confidence, lack of motivation, and timidity. Based on the findings it can be suggested that school principals should consider the effects of positive administrative attitudes on the development of students. Article visualizations
