Families with young children with and without developmental disabilities often create a musically rich home environment. Parent-child music engagement, like singing play songs, is associated with positive outcomes for children, parents, and their relationship. However, little is known about if the home music environment differs across diagnostic groups and if parent-child music engagement relates to parent-child affective attachment across families of diagnostically diverse children. Using an online questionnaire, the current study examined the home music environment of 340 families with young children with typical and atypical development. A variety of musical activities were common in all diagnostic groups. Diagnostic groups differed in active musical engagement, potentially relating to the differing phenotypes of various developmental disabilities. Parent-child music engagement was associated with parent-child affective attachment, even when controlling for relevant variables. Promoting musical engagement at home and through parent-child therapy may be an accessible way to support parent-child relationships.