Children’s Centres are widespread in England and comprise multi-professional staff teams seeking to work with families with children aged 0–5 years. Although parent–child group music sessions appear frequently in Children’s Centre activity programmes, the rationale for their inclusion remains unclear. This article presents the results from phase two of an exploratory mixed-methods study which investigated the role of and rationale for parent–child (0–3 years) group music making activities in Children’s Centres. The perceptions of parents and practitioners were considered, and differences were found between them. The themes generated by the initial qualitative interview study (phase one) were investigated further in this quantitative questionnaire study (phase two), which involved 49 practitioners and 91 parents. Seven thematic categories of the perceived benefits of music—Social, Emotional, Learning, Teaching, Links to Home, Parenting, and Organisational—which had been identified in the interview study, were used as the basis of the design of the questionnaire. Statistical analyses revealed some significant differences between the expressed views of parent and practitioner groups, as well as between parents in different broad age groups. Practitioners expressed more positive views about the perceived benefits of music for parents than were expressed by the parents themselves. Parents in the majority age group (27–35 years) appeared to express significantly more positive opinions on a variety of questionnaire items than did parents in both younger and older age groups. Working practices of Children’s Centre practitioners appear to include music group activities for which they have had little training. A new practitioner role is proposed: that of social music pedagogue. The questionnaire results have augmented and enhanced the findings of the interview study and suggest that the rationale for parent–child music group activities in Children’s Centres is centred on the benefits for children’s social, cultural, emotional and cognitive development.