From historical points of view Naturalism has greatly influenced Western education both in the aspect of educational theory and educational practice. In the past the Naturalis-tic educators discovered that in the affairs of man's education man is a part of nature and he cannot separate himself from it. Like other life forms rnan is a growing being affected by biological rules and natural laws. Thus the education of man should follow the path of natural development, not the customs of human society. Education is a process of natural development from within. It is incorrect to consider that education is a process of formation from without. In regard to the practice of education, Naturalism has strongly emphasized the value of early education of children. The Naturalist also regards children as independent individuals. Freedom, activity, growth and experience are the watch-words of the Naturalis-tic educators. Therefore, that the child-centered education movement and the progressive education movement in the United States of America have been derived frqm Naturalism is accepted by most educational historians in the Western World.This study tries to concentrate on the following aspects: the main suggestions of Naturalism in regard to man's position in the kingdom of nature and his relation to nature, the educational principles of Naturalism, the ideas of Naturalistic teachers, the contributions of the Naturalistic educators of the West, and a brief conclusion.