This study investigates the impact of women's political representation on children's health outcomes from 1990 to 2020 using a global dataset comprising 162 countries. The child health outcomes studied are infant and neonatal mortality rates and vaccination coverage for measles and diphtheria, pertussis, and tetanus (DPT). We apply an event study and panel data instrumental-variable fixed-effects regression analysis for data analysis. The timing of the introduction of a gender quota in a country is used as an instrument to address endogeneity bias commonly associated with women's political participation. We find evidence of a positive impact of increasing women's representation in national legislatures on all child health outcomes studied. In particular, our study reports a significant negative effect of women's political participation on neonatal mortality which was not reported by any previous research. We also find evidence to support hypotheses related to several potential pathways that connect women's political representation with child health outcomes, including health expenditure, female labor force participation, skilled birth attendance, and adolescent fertility rate. Also novel in our findings is a heterogeneity analysis which reveals that reserved seat quota boosted child health outcomes more than candidate quota, with strong geographical variation in the relationship. Sub-Saharan Africa and South Asia benefited the most in terms of child health outcomes due to an increase in women's political representation among all regions. Our findings reinforce the significance of women's greater political empowerment for child health—a crucial development outcome—particularly in regions characterized by the poor quality of early childhood health conditions and survival rates.