In order to create an initial framework for learning-by-teaching, this article reviews a body of relevant research, from a historical perspective, gathering evidence about the potential and the limits of this pedagogical mechanism. Results indicate that the more complex the teaching activity is, the more opportunities there are to learn by teaching. This explanatory framework may help to develop a conception of teaching and learning consistent with the Knowledge Society and to promote the incorporation and extension of practices that provide opportunities for students to learn by teaching their peers, such as cooperative learning, peer tutoring or peer assessment.