Background: A range of studies report a robust association between family socioeconomic position and the prevalence of child overweight/obesity. On average, children from poorer backgrounds are more likely to be overweight/obese than children from more advantaged families. However, a small number of US studies have shown that, for ethnic minority children, the association is either nonexistent or reversed.

Objective: We test if the link between socioeconomic position and child overweight/obesity at age 7 is heterogeneous in the United Kingdom where rates of obesity are particularly high for some groups of ethnic minority children.

Methods: We use nationally representative data from the UK Millennium Cohort Study as well as descriptive analyses and logistic regression models.

Results: Poorer White children are at higher risk of overweight/obesity than higher income White children. However, socioeconomic disparities are reversed for Black African/Caribbean children and nonexistent for children of Indian and Pakistani/Bangladeshi origin. Moreover, the health behaviours that explain socioeconomic disparities in child overweight/obesity for the White group appear to be irrelevant in explaining differences by socioeconomic position for the Black Caribbean and African groups.

Conclusions: We should be careful in assuming that higher socioeconomic position is protective against child overweight/obesity for all groups of the population.

Contribution: This study shows for the first time important variation by ethnicity in the link between socioeconomic position and child overweight/obesity – and in the underlying mechanisms linking them – in the United Kingdom.