Poor educational attainment is a persistent problem among US hispanic children, relative to non-hispanics. Many of these children are immigrants and/or come from households that use a minority language in the home. This paper examines the effects of participation in a government sponsored preschool program called Head Start on these children. We find that large and significant benefits accrue to Head Start children when we compare them to siblings who did not participate in the program. On average, Head Start closes at least 1/4 of the gap in test scores between hispanic children and non-hispanic white children, and 2/3 of the gap in the probability of grade repetition. However, we find that the benefits of Head Start are not evenly distributed across sub-groups. © Elsevier Science S.A.