There is increasing consensus among psycho-educational scholars about argumentation as a means to improve student knowledge and understanding of subject matter. In this article, we argue that, notwithstanding a strong theoretical rationale, causal evidence is not abundant, definitions of the objects of study (argumentation, learning) are often not well defined, and the variance in research methods is large. We argue that we systematically review the available research evidence by mapping it on the Argumentation For Learning research framework, which specifies the different "antecedents, dialogue characteristics," and "learning outcomes" of argumentation. In doing so, we identify claims that are supported with substantive empirical evidence and demonstrate which questions are still open to further empirical examination. We also uncover several promising, relatively unexplored venues for future research.