Background: Postnatal depression affects between 6 and 13% of new parents, but only a small proportion of individuals who meet diagnostic criteria receive optimal treatment. One reason for this is poor mental health literacy of postnatal depression.Aims: Studies have examined mental health literacy of maternal postnatal depression, but there are no similar studies of paternal postnatal depression, which we sought to rectify.Methods: A sample of 406 British adults was presented with vignettes describing cases of either maternal or paternal postnatal depression. Based on the vignettes, participants were asked to report if they thought anything was wrong with the targets and, if so, to describe what they thought was wrong. Participants also rated the targets on a range of attitudinal dimensions.Results: Participants were more likely to indicate that something was wrong when the target was female (97.0%) compared to male (75.9%). Of those who believed something was wrong, 90.1% of participants correctly described the female target as experiencing postnatal depression, but only 46.3% did so for the male target. Participants also held more positive attitudes toward the female target than the male target.Conclusions: There is a gender binary in symptom recognition of postnatal depression, which highlights the need for greater awareness of paternal postnatal depression.