Concepts are at the core of human psychological experience. By means of them, we can communicate, understand and collaborate with each other. Within each community, concepts have been learned and can be taught. They are of capital importance for education in every level and for work activities. Concepts have been the object of study of different disciplines and in different contexts for many years. Despite their importance and the attention they have received, both common sense and psychological science understand concepts in an oversimplified way that has consequences for research and teaching. Early in the past century, Vygotsky studied the phenomena of concepts and their development in what ended up addressing most of the loose ends that remain in current dominant psychological and educational perspectives. In this article, we review the main, hegemonic perspectives on concepts in psychology, particularly one of the mayor research fields in educational psychology (Research on Conceptual Change), to present later some cross-cutting criticisms to those approaches that will become our touchstone for a sound theory of concepts. Then we present the Vygotskian approach to concept development, and the methodological implications derived from the dialectical framework in which it is inscribed. Finally, extending the Vygotskian approach beyond child development, we present a method developed in French work psychology, the Activity Clinics approach, and its potential for studying the development of concepts in work activities.