ObjectivesWe aimed to investigate the socioeconomic inequalities in the burden of underweight and overweight among children in South Asia. We also examined other factors that were associated with these outcomes independently of household’s socioeconomic status.DesignNationally-representative surveys.SettingsDemographic and Health Surveys from Bangladesh, India, Pakistan, Maldives and Nepal, which were conducted between 2009 and 2016.ParticipantsChildren aged 24 to 59 months with valid measurement for height and weight (n=146 996).Primary exposure and outcome measuresPrimary exposures were household’s wealth index and level of education. Underweight and overweight were defined according to the WHO and International Obesity Task Force definitions, respectively.ResultsUnderweight prevalence was 37% in Bangladesh, 38% in India, 19% in Maldives, 29% in Nepal and 28% in Pakistan. Bangladesh, India and Nepal had similar overweight prevalence (between 2% and 4%) whereas Pakistan (7%) and Maldives (9%) had higher prevalence. Households with higher wealth index or education had lower odds of having underweight children. Adjusted ORs of underweight for richest versus poorest households were 0.4 (95% CI: 0.3 to 0.5), 0.5 (95% CI: 0.5 to 0.6), 0.5 (95% CI: 0.2 to 1.4), 0.5 (95% CI: 0.3 to 0.8) and 0.7 (95% CI: 0.5 to 1.1) for Bangladesh, India, Maldives, Nepal and Pakistan, respectively. Compared with poorest households, richest households were more likely to have overweight children in all countries except Pakistan, but such associations were not significant after adjustment for other factors. There were higher odds of having overweight children in households with higher education in Bangladesh (OR 2.1 (95% CI: 1.3 to 3.5)), India (OR 1.2 (95% CI: 1.2 to 1.3)) and Pakistan (OR 1.8 (95% CI: 1.1 to 2.9)) when compared with households with no education. Maternal nutritional status was consistently associated with children’s nutritional outcomes after adjustments for socioeconomic status.ConclusionsOur study provides evidence for socioeconomic inequalities for childhood underweight and overweight in South Asian countries, although the directions of associations for underweight and overweight might be different.