There is a paucity of research, training, and material available to support supervisors of undergraduate dissertation students. This article explores what "good" supervision might look like at this level. Interviews were conducted with eight new supervisors and six dissertation coordinators using a critical incident methodology. Thematic analysis of interview transcripts indicated that both supervisors (themes "directed and clear advice" and "instilling confidence") and students (themes "interest in topic" and "ownership") contributed to "good" supervisory experiences (theme "evolving relationships"). Issues affecting this process were identified. Resources developed from these findings may be adapted by academic developers for supporting new dissertation supervisors.