This study investigated the effect of family planning on the levels of women’s anaemia and child undernutrition at the aggregate level using the compiled databases of the World Bank, UNICEF and the Economist Intelligence Unit. Correlation scatter matrix plots and multivariate OLS regression models were employed to assess the effect of family planning on women’s anaemia and child nutritional status across countries. At the aggregate level, the bivariate correlation estimates found that the Contraceptive Prevalence Rate (CPR) was negatively associated with women’s anaemia (r=−0.62, p<0.01), child underweight (r=−0.57, p<0.01) and child stunting (r=−0.63, p<0.01). The results of the OLS regression showed that the independent effect of CPR on women’s anaemia (β=−0.35, p<0.01), child underweight (β=−0.13, p<0.01) and child stunting (β=−0.18, p<0.05) was negative, even after controlling for child marriage, female literacy, per capita GDP, poverty ratio, health expenditure and food security. The synthesis of these findings with the existing literature based on micro-data suggests pathways through which family planning influences the nutritional status of women and children. Family planning helps in avoiding shorter birth intervals, unintended pregnancy and unsafe abortion, which would otherwise result in nutrient depletion among mothers and further increase the risk of undernutrition in their children.