Using a state panel from 1940–2010, I examine the impact of immigration on the high school completion of natives in the United States. Immigrant children could influence native children's educational experience as well as their expected future labor market. I find evidence for both channels and a positive net effect. An increase of one percentage point in the share of immigrants in the population aged 11–64 increases the probability that natives aged 11–17 eventually complete 12 years of schooling by 0.3 percentage point. I account for the endogeneity of immigrant flows by using instruments based on 1940 settlement patterns.