To understand educational administration as a science, one must acquire some sense of basic concepts on educational adminstration systematically. This paper, as a first attempt in this field for the writer, has traced some of significant developments of educational administrative theory in general in relation to the other fields of administration, particularly, public administration. Through an evolutionary process, educational administration has passed three differentiable eras. Roughly speaking, the three eras might be as follows. First, from about 1900 to 1930, era of scientific management, during which school administors, like Spaulding and Bobbitt, were managing school in a manner similar to efficient and productive factories. School administors acquired knowledge by means of “job-analysis” influenced by Taylor's classical theory. Second, human relations era (1930-1950), which modified scientific management severely by directing attention to the human side (psychological and social aspect) of administration, influenced by the Hawthorne studies conducted by Mayo and Roethlisberger. The human relations movement became intimately associated with “democratic adimistration” in schools, since both emphasized group action and the value of individuals. The new concepts such as “morale,” “group dynamics,” “democratic supervision,” and “personnel relations” were available to the educational administrators to use in approaching their work. Now we are at the third era, the era of administive theory or “new” theory (1950~). Inspired by Barnard and Simon, many social and behavioral scientists were attracted to create a administrative theory based on scientific inquiry. One of the goals of the “new” administrative theory is to adopt models from other discipines which are applicable to educational administration. More attention is being given to “administrative behavior,” “role,” “organizaition,” “power structure,” “decision-making,” “systems approach,” etc. In current Korean educational administrative situation, we have teen suggested in this brief historical review that such concepts emphasized in each era respectively as efficiency, human relations, and new administrative theory should be equally needed in urgency at a time.