Research suggests that parental reflective functioning (PRF)—that is, the parent’s capacity to envision the mind of the child—is a key factor in understanding the child’s reflective capacities. Yet, most existing measures of PRF assume that it is a broad trait-like feature. This study investigated cross-sectional relationships between domain-specific PRF, operationalized as mothers’ estimates of the Theory of Mind (ToM) capacities of their children (mother’s ToM estimates; MTE), and ToM acquisition in 83 preschool children, using a multidimensional approach. Results showed that the accuracy of MTE was positively related to the children’s capacity for ToM, while the degree of certainty of inaccurate MTE was negatively related to ToM acquisition. The implications of these findings for the conceptualization of PRF and its relationship to ToM and other features of social cognition in children are discussed.