As states have upgraded their commitment to pre-K education over the past two decades, questions have arisen. Critics argue that program effects are likely to fade out or disappear over time, while supporters contend that program effects are likely to persist under certain conditions. Using data from Tulsa Public Schools, three neighboring school districts, and the state of Oklahoma, and propensity score weighting, we estimate the effects of Tulsa's universal, school-based pre-K program on multiple measures of academic progress for middle school students. We find enduring effects on math achievement test scores, enrollment in honors courses, and grade retention for students as a whole, and similar effects for certain subgroups. We conclude that some positive effects of a high-quality pre-K program are discernible as late as middle school.