Background: The meanings of neurodevelopmental conditions are socially and culturally defined. We explored how parents of a child with Down syndrome experienced public and professional understandings of Down syndrome. Method: Qualitative interviews with 25 parents of a child with Down syndrome living in Denmark. From a reflexive thematic analysis, we developed themes describing understandings (i.e., attitudes or perceptions) of Down syndrome. Results: The parents experienced that the Down syndrome diagnosis acted as a 'label'; this had perceived positive and negative consequences for the child. The parents felt others understood Down syndrome as severe and undesirable. This attitude was tied to the existence of prenatal screening. Finally, to the parents, professional support for their child expressed an understanding of children with Down syndrome as valued individuals. Conclusions: Parents encountered ambiguous understandings of Down syndrome. This should be recognised by professionals who may shape such understandings.