<p>Early research has noted the importance of interactions between parents and teachers about young children’s engagement with mathematics, yet little is known about how these interactions unfold. In early childhood education and care, interactions about what mathematics is for young children and how they should engage with it can become spaces where only certain knowledge becomes accepted as valuable. In this study, photo-elicited focus group interviews in which teachers and parents discussed their own photos of mathematics learning activities were analysed using Foucault’s understandings of power and knowledge. This analysis showed how the institutional roles of teachers and their positioning of parents’ knowledge about their children’s mathematics education affected the potential for collaboration in these interactions. Although teachers’ pedagogical and professional knowledge often took precedence, parents sometimes challenged teachers’ positioning of themselves as more knowledgeable. The circulation of power and knowledge affected not only what came to be valued, but also how the different roles of the participants contributed to the possibilities for collaboration, which appeared in the interactions. These findings provide insights into why collaboration about mathematics education may be difficult to achieve and have implications for parental involvement in early mathematics education. This article is part of a special issue titled “Parents, caregivers and community in mathematics education”. To see other articles in this issue please select <a href="https://link.springer.com/collections/cibgdgbdfj">https://link.springer.com/collections/cibgdgbdfj</a>.</p>