In this paper, we address the need to develop an empirically-based understanding of the use of dialogue in teaching by discussing theory and research related to a pedagogical approach called collaborative reasoning (CR). CR is an instructional method designed to engage elementary school children in group discussions about controversial issues raised in their readings. CR is grounded in social learning and schema-theoretic views of cognition, which are integrated to form a new model, called argument schema theory (AST). According to AST, students acquire generalizable knowledge of argumentation, or an argument schema, through participating in dialogic discussions with their peers. The article reviews empirical evidence from a variety of studies designed to evaluate the educational potential of dialogic interactions. The studies investigated group processes during CR discussions, individual student outcomes following participation in discussions, and the connections between the features of social interaction and individual student performance. We conclude that, despite its complexity, classroom dialogue can serve as a useful mechanism for promoting the development of individual argumentation. (Contains 4 tables, 1 figure and 2 notes.)