The parents’ capacity to reflect upon the psychological processes in their child,termed parental reflective functioning (PRF) can be impaired by parental mentalhealth problems. The present study aimed to investigate the factor structure ofan infant version of the Parental Reflective Functioning Questionnaire (PRFQ-I)in a low-risk sample of 259 Danish fathers of 1–11-month-old infants to investi-gate measurement invariance of the PRFQ-I between fathers and mothers; andto examine the association between PRF and paternal depressive symptoms, psy-chological distress, and parenting stress. Confirmatory factor analysis supporteda three-factor model of the PRFQ-I. Multi-group factor analysis indicated par-tial measurement invariance. Multiple linear regressions showed that paternaldepressive symptoms were not associated with PRF. There was an interactioneffect of paternal depressive symptoms and general psychological distress onpaternal interest and curiosity in their infant’s mental state and certainty ofinfantmentalstate.IncreasedparentingstresswasassociatedwithimpairedPRFon all three subscales of the PRFQ-I. These results provide further evidence for amultidimensional, brief assessment of paternal reflective skills and insight intohow variability in paternal psychological functioning relates to impaired PRF inthe postpartum period.