Dialogic educators have designed strategies to facilitate dialogic teaching, such as establishing ground rules, employing talk moves, and structuring discussions. Though productive, such strategies rarely open dialogic space, in which shared meaning is created through an interaction that blurs the boundaries between participating voices. Dialogic space is facilitated by tension between perspectives; openness to others, which is facilitated by ego suspension, authority relaxation and respect for and interest in others; and acceptance of dialogue's inherent unpredictability. We explore classroom episodes in which dialogic space did and did not emerge, highlighting the importance of playfulness and mutual attunement for maneuvering within dialogic space. These cases also point to 4 challenges that dialogic space poses: tension between curricular coverage and dialogue's unpredictability; the demands such unpredictability makes on teacher flexibility, knowledge and judgment; equity in the distribution of teacher attention and student participation; and the threat of losing control.