ObjectiveAlthough the association between child malnutrition and maternal employment status has been widely studied in several developing countries, the causal effect of mothers’ employment on their children's health remains largely unknown. The aim of this study was to examine the causal effect of maternal employment on child malnutrition in five South Asian countries. MethodThis study used a data set of >55 200 children ages 0 to 5 y by pooling the most recent Demographic Health Surveys (DHS) from Bangladesh, India, the Maldives, Nepal, and Pakistan. An instrumental variable (IV) method was applied to measure the causal effect of the mother's employment status (working mother) on stunting and underweight among children. ResultsResults showed that of the children in South Asia, 37.9% and 33.6% were stunted and underweight, respectively. The IV estimates suggested that maternal employment significantly increased stunting and underweight in children. For example, the likelihood of stunting and underweight increased by about 9.5% and 6.3% points, respectively, in South Asia when mothers worked. The likelihoods in Bangladesh (39.9 and 26.6%) and Pakistan (28 and 33.4%) were high but were at moderate levels in India (5.3 and 4.2%) and Nepal (8 and 9%). ConclusionsIn the present study, an adverse effect of maternal labor market participation on the nutritional status of under-five children in South Asian countries was found. These findings could be helpful for policymakers in South Asian countries to adopt suitable policies to reduce malnutrition among children, especially for the children of employed mothers.