摘要: We estimate the impact of having an older sister (rather than an older brother) on early childhood development in a sample of rural Kenyan households with otherwise similar family structures. Older sibling gender is not related to household structure, subsequent birth spacing, or other observable characteristics, so we treat the presence of an older girl (as opposed to an older boy) as plausibly exogenous. Having an older sister improves younger siblings’ vocabulary and fine motor skills by more than 0.1 standard deviations. Impacts on physical development outcomes are concentrated near the bottom of the distribution. Impacts are not driven by changes in parental investments in younger children. Sisters do more direct stimulation of their younger siblings than brothers, and this leads to improvements in young children’s development outcomes. JEL codes: O12, J13, J16, D13