认知发展论（Cognitive-developmental theory 或 Theory of Cognitive Development）是著名发展心理学家让·皮亚杰所提出，被公认为20世纪发展心理学上最权威的理论。所谓认知发展(cognitive development)是指个体自出生后在适应环境的活动中，吸收知识时的认知方式以及解决问题的思维能力，其随着年龄增长而改变的历程。皮亚杰的研究方法不采用当时流行的等实验组及多人数据统计的方式，而采用对于个别儿童(他自己的女儿)在自然的情境下连续、细密的观察纪录他们对事物处理的智能反应，属于质的研究。而他这种研究方式，广为现时儿童心理学家所采用。

Piaget's theory of cognitive development is a comprehensive theory about the nature and development of human intelligence. Piaget believed that one's childhood plays a vital and active role in a person's development. Piaget's idea is primarily known as a developmental stage theory. The theory deals with the nature of knowledge itself and how humans gradually come to acquire, construct, and use it. To Piaget, cognitive development was a progressive reorganization of mental processes resulting from biological maturation and environmental experience. He believed that children construct an understanding of the world around them, experience discrepancies between what they already know and what they discover in their environment, then adjust their ideas accordingly. Moreover, Piaget claimed that cognitive development is at the center of the human organism, and language is contingent on knowledge and understanding acquired through cognitive development. Piaget's earlier work received the greatest attention. Many parents have been encouraged to provide a rich, supportive environment for their child's natural propensity to grow and learn. Child-centered classrooms and "open education" are direct applications of Piaget's views. Despite its huge success, Piaget's theory has some limitations that Piaget recognized himself: for example, the theory supports sharp stages rather than continuous development (decalage).