This paper investigates how teachers at Norwegian early childhood education and care (ECEC) institutions interpret the national curriculum’s mandate that children should learn about religion and religious festivals. The results from an empirical study conducted in one religiously diverse ECEC, which is attended by children from both Christian and Muslim families, serve as the context for this analysis. The study identifies discrepancies between the ideal provided by the national curriculum and the reality described by teachers and parents. In the case of the ECEC studied, religion as such causes uneasiness among the teachers. As a result, Christian festivities focus more on traditions than religion, and Muslim holidays are ignored. Parents are largely uninformed about the purpose and content related to religious festivities at their children’s ECEC. A starting point in addressing teachers’ uncertainty over how to comply with the curricular mandate is to design pedagogical activities around religious festivities that aim to achieve learning and mutual understanding among the children.