We investigate the effect of Head Start on education and wage income for individuals in their 30s using the NLSY79. We contribute to the existing literature by examining distributional effects, using an approach that relies on two weak stochastic dominance assumptions that can be checked using pre-Head Start cohorts. We find that Head Start has positive and statistically significant effects on years of education and wage income. We also uncover important heterogeneity in the effectiveness of the program; the effects are concentrated at the lower end of the distribution, and the effects are strongest for women, blacks and Hispanics. Joint with Edwin Leuven.