It is now widely believed that classroom dialogue matters as regards student outcomes, with optimal patterns often regarded as requiring some or all of open questions, elaboration of previous contributions, reasoned discussion of competing viewpoints, linkage and coordination across contributions, metacognitive engagement with dialogue, and high student participation. To date, however, the relevance of such features has been most convincingly examined in relation to small-group interaction among students; little is known about their applicability to teacher-student dialogue. This article reports a large-scale study that permits some rebalancing. The study revolved around 2 lessons (covering 2 of mathematics, literacy, and science) that were video recorded in each of 72 demographically diverse classrooms (students' ages 10-11 years). Key measures of teacher-student dialogue were related to 6 indices of student outcome, which jointly covered curriculum mastery, reasoning, and educationally relevant attitudes. Prior attainment and attitudes were considered in analyses, as were other factors (e.g., student demographics and further aspects of classroom practice) that might confound interpretation of dialogue-outcome relations. So long as students participated extensively, elaboration and querying of previous contributions were found to be positively associated with curriculum mastery, and elaboration was also positively associated with attitudes.