Integrated services in preventive health care and child and family social work increasingly embrace the concept of proportionate universalism (PU) as a means of overcoming the dichotomy between universal and targeted services in contexts of diversity. The implementation of the concept of PU raises several theoretical and empirical questions that form the basis of this article. This study aims to provide more insight in how the concept of PU is operationalized in child and family social work. Qualitative research was performed in three specific cases of child and family social work, the so‐called “Huizen van het Kind” or Children’s Houses in Flanders (Belgium). The study triangulates three perspectives: policy, organizational level, and street level. The findings generate three meta‐themes: perseverant structuring of populations or predefinitions, image and conceptualization of the Children’s House, and organizational challenges. These results reveal a difference between the theoretical assumption of PU and the practical implementation in child and family social work.