We study the impacts of prenatal sex selection on girls’ well‐being in India. We show that high sex ratios at birth reflect the practice of prenatal sex selection and apply a triple difference strategy to examine whether changes in health outcomes of girls relative to boys within states and over time are systematically associated with changes in sex‐ratios at birth. We find that an increase in prenatal sex selection leads to a reduction in girls’ malnutrition, in particular, underweight and wasting. We further explore various underlying channels linking between prenatal sex selection and girls’ outcomes.