Knowledge about the antecedents of collective psychological ownership (CPO) in family firms is limited, despite its relevance for theory and practice. To address this gap, we adopted a multilevel configurational approach, encompassing organizational and individual attributes, to consider multiple possible combinations of the causal determinants of the perception of CPO over the organization. The empirical data comprise a sample of 162 individuals from 33 privately held family businesses in Belgium. More specifically, we conducted a fuzzy set qualitative comparative analysis (fsQCA), which was particularly appropriate given the aims of our study. By identifying distinctive configurational paths and three key mechanisms operating across such paths (socialization, identification and signaling), our results offer two important contributions. First, we contribute to the conceptual understanding of the antecedents of CPO in family firms, both for family and non-family members. Second, we expand the general literature on the paths leading to CPO by proposing an approach that combines individual attributes with organization-level features.