There is an increasing development of courses and course components taught through teaching and learning dialogues online yet there is little secure knowledge regarding the educational quality of these dialogues. Drawing on contemporary sociocultural research, this paper adapts a well-established analytical framework (see Mercer, 1995) that has been developed to understand face-to-face educational dialogues to the context of asynchronous electronic conferencing. The work reported is derived from an in-depth case study of a tutorial group of 11 students enrolled on a course within the Open University's MA in Open and Distance Education. The course was taught online to an international cohort of students from wide-ranging academic backgrounds. The analyses of electronic conference archives presented here focus on understanding the students' online collaborative work and the ways in which they constructed meaning, negotiated shared understanding and supported each other in the process of learning at a distance. The implications of the findings for educational practice are considered.