This chapter discusses how learning outcomes can be improved by focusing educational systems on developing expertise in reasoning. A small but growing body of international research suggests that a wide variety of students can develop expertise in argumentation, and by extension, expertise in reasoning. Studies show that argument-based classroom talk can lead to the acquisition and retention of general knowledge, beyond the topics taught through discussion. The chapter considers how teachers develop expertise in this form of teaching, often called “dialogic,” and outline some of the challenges to spreading dialogic teaching beyond elite classrooms. It looks at how systems build organizational expertise to support dialogic teaching and learning, which involves considering the social and institutional structures within which teachers work. Finally, in a discussion of future research in this field, the chapter calls for engaging all levels of the educational system in supporting practices that will grow powerful learning.