In developmental psychology, one of the questions that garners the attention of clinicians and experimental psychologists is caregiver bias in child’s psychological problems reports. Different models suggested by developmental psychology (e.g. The Depression-distortion, Accuracy and Combinatory model), had discussed the relation between the mother’s objective description of a child’s mental state and the degree of bias in her report. Recent evidence suggests that such bias could respond to a deficit in the caregiver’s ability to access, monitor and regulate their own psychological contents. The hypothesis to investigate is if such ability in caregivers, known as metacognition, could modulate the quality of mental attributions in the children. To this end, we recruited 102 Chilean mothers-children dyads users of the public care system in the city of Santiago. In an experimental setting, we evaluated metacognition in the mother through a perceptual metacognition task in addition to different psychopathology questionnaires (SCL-90-R & STAI) and biological reactivity to stress (TSST). By questioning the mother, we also investigated her belief about psychological symptoms in the child (CBCL 1½ - 5). Our results indicate that maternal severity and quantity of symptoms predict maternal reports of problematic psychological states in their child only in caregivers who show low metacognitive efficiency. We conclude the article with a discussion of the link between metacognitive capacity and the ability to attribute mental states to third parties.