Child malnutrition is a significant public health concern in several developing countries. Evidence suggests that family size and children’s health outcomes are correlated. We utilize data from the National Family Health Survey (NFHS-5) for India and employ an Instrumental Variable approach to examine the impact of limiting fertility through the use of contraceptives on child health. Exploiting the exogenous variation in district average of women’s exposure to family-planning messages, we estimate that contraception leads to a 1.45 (0.47) SD increase in a child’s height-for-age (weight-for-age) z-scores and reduces the likelihood of stunting (being underweight) by 17.9 (10.9) pp. We provide support to the resource-dilution hypothesis as our potential mechanism, highlighting that an exogenous increase in household size, explained by multiple or twin births, depletes children’s health. Our findings underscore the benefits of exposure to family-planning for child health and the need for targeted policies focusing on access to (and use of) contraceptives.