Theory of mind (ToM) development is fostered by parent-child interactions characterized by accurate reflection on the child's mental states, or reflective function (RF), by the caregiver. Therefore, attachment-based RF is the foundation upon which children learn to reason about minds outside the attachment context (domain-general ToM). However, it is not known to what extent attachment-based RF of the self versus caregivers uniquely relates to domain-general ToM. Additionally, it is likely that for psychopathology associated with maladaptive parent-child dynamics (i.e., borderline pathology), domain-general ToM impairments are more strongly related to attachment-based RF disturbances. Therefore, the aim of the current study was to evaluate associations between domain-general ToM and attachment-based RF to determine whether RF of the self versus caregivers has unique relations to domain-general ToM. Second, we tested whether borderline pathology would moderate this relation. Among a sample of inpatient adolescents (N = 330 adolescents; Mage = 15.40, SD = 1.44), findings suggest that RF of the self uniquely relates to domain-general ToM and that this relation is strongest among adolescents with high levels of borderline pathology. Therefore, evidence supports theory regarding the association between attachment-based RF and domain-general ToM. Additionally, interpersonal disturbance observed in borderline pathology, even in adolescence, is related to attachment-based social-cognition.