This paper discusses educational planning activities in which the Organization for Economic Co-operation and Development (OECD) has had some involvement. Only a part of these activities are dealt with--national educational planning within the context of economic and social development. An attempt is made to show how OECD's work in educational planning has led almost inevitably to the adoption of a "systems approach." Emphasis is placed on the relative merits of the "manpower" approach and the "social demand" approach to educational planning, and on how these two approaches have not been about educational planning as such, but about different criteria for establishing the objectives or goals of the educational system. An example is given of a model of the dynamic structure of the educational system in terms of student flow. (hw)