The aim of this study was to examine the relationship between obesity and self-esteem in children in relation to specific domains of their self-perception, and further to explore the extent to which this may vary by gender and economic circumstances. A total of 211 children aged 8-9 years drawn from both advantaged and disadvantaged areas of Belfast completed the Harter Self-Perception Profile for Children and measures of body mass index were obtained. Overweight, impoverished children had significantly reduced social acceptance and physical competence scores. Boys had significantly lower scores than girls in the behavioural conduct domain. Girls had significantly lower scores than boys for the athletic competence. These results suggest that risk factors of increased weight and impoverished backgrounds have a combined negative effect, placing some children at increased risk of having lower self-perceptions in some, but not all domains. Health interventions for childhood obesity should consider the likelihood of specific relationships between physical and psychosocial factors.