The main purpose of this thesis is to define and discuss the concept of morality from the perspective of school moral education. To this end, in order to reduce confusion due to terminology, the common characteristics and discriminatory characteristics of the terms 'moral' and 'ethic' are reviewed first. Based on this, the concept of morality is presented from the multidisciplinary perspectives and its characteristics are discussed. The author found the source of morality in the harmony between altruism and selfishness, which are universal human characteristics. The immoral problems we experience in our daily life are usually manifested by selfishness invading or suppressing the realm of altruism. In that context, morality is defined as the psychological disposition or ability to seek, aspire to, and act in accordance with the optimal balance of altruism and selfishness. It is expected that this will provide educational implications for educators who are dedicated to designing future moral education curriculum or cultivating students' morality in school moral education.