Abstract: Reflection figures prominently in curricula around the world, and especially in play-centred pedagogies. For instance, the Pedagogy of Play, developed here at Project Zero, True Play in the Anji Province of China, and Reggio Emilia in Italy, all name reflection in their key principles and practices. But what is reflection, and how does it relate to play? In this talk, we will revisit what we know about reflection in formal learning and share insights from the participatory research study group on reflection at the International School of Billund in Denmark, as well as other examples from across the world.