The global prevalence of childhood obesity is alarmingly high. Parents' identification of their children as overweight is thought to be an important prerequisite to tackling childhood obesity, but recent findings suggest that such parental identification is counterintuitively associated with increased weight gain during childhood. One possibility is that parental identification of their child as being overweight results in that child viewing his or her body size negatively and attempting to lose weight, which eventually results in weight gain. We used data from two longitudinal cohort studies to examine the relation between children's weight gain and their parents' identification of them as being overweight. Across both studies, children whose parents perceive them to be overweight are more likely to view their body size negatively and are more likely than their peers to be actively trying to lose weight. These child-reported outcomes explained part of the counterintuitive association between parents' perceptions of their children as being overweight and the children's subsequent weight. We propose that the stigma attached to being recognized and labeled as "overweight" may partly explain these findings.