Mentalizing is, to a certain extent, considered context specific. However, research on the association between parents’ abilities to reflect upon their infant's mental states outside social interaction (offline) versus during ongoing parent-infant interaction (online) is currently limited. This study investigated the association between self-reported offline and online mentalizing in a sample of primarily ethnically Danish mothers (N = 142), with symptoms of postpartum depression, and their 1–11-month-old infants. Offline mentalizing was assessed with the Parental Reflective Functioning Questionnaire—Infant Version (PRFQ-I) and online mentalizing was assessed with interactional mind-mindedness. Ordinal logistic regressions showed that a higher score on the PRFQ-I prementalizing subscale was negatively related to number of overall mind-related comments and appropriate mind-related comments produced by mothers during interaction with their infant. Our results indicate partial overlaps between self-reported parental reflective functioning and mind-mindedness, that is, that particularly offline maladaptive mentalizing is associated with lower levels of mentalizing during interaction in mothers with symptoms of depression. Post-hoc examination of the interaction effect of postpartum depression showed that this association was only evident in mothers with medium to high levels of depression. Findings and implications are discussed.