The aim of the study is to contribute to the literatüre by comparing Henry Wallon’s and Jean Piaget’s views on cognitive development. Wallon, like Piaget, has made a general childhood and adolescent development theory. He cast the foundations of ontogenic studies (individuality) independent from classical methods. He tried to understand the individual's development process through rich observations to overcome the introspective, psychological parallelism approaches which were dominant in that period. At the end of his studies, two main results were obtained. First, he tried to show how biological, affective, social and mental factors are effective in a relation with the whole called as human. Secondly, it has diversified the review subjects and methods to examine how the system consisted of these factors works. In this context, he used physiological, statistical, structural, psychoanalytic methods according to the situation. According to Wallon, development can be explained by the interaction between social conditions related to neurobiological maturation and adaptation conditions. Wallon considered development as six stages. Piaget, on the other hand, explained the development in four stages. It can be argued that Wallon is more concerned with the child's consciousness process related to him/herself, and Piaget tried to explain the cognitive development of the child through his/her relation to the objects. Wallon also led away from Piaget in psycho-social terms. Piaget tried to explain the development in a linear and orthogenetic way, and Wallon considered it as an epigenetic and intermittent process. Unlike Piaget who claimed that the other stage did not begin until one stage had ended, Wallon argues that the developmental stages were carried out with complex, transitive (between the physical development and central nervous system - alternately), intertwining conflicts and crises.