This quantitative correlational study examines school-level longitudinal outcomes of eighth-grade algebra universal acceleration in 15 U.S. school districts when compared with selective acceleration in 289 school districts. Universally accelerated school districts had higher enrollments, with large effect sizes, in geometry, algebra 2, and Advanced Placement (AP) Calculus AB and BC; however, no differences were observed in mathematics performance. A second analysis used a sample with equivalent socioeconomic profiles. Universally accelerated districts had higher enrollments, with moderate effect sizes, in only geometry and algebra 2, yet lower performance, with moderate to large effect sizes, in geometry, AP Calculus AB, and AP Statistics. The validity of these results may have been threatened by fluctuations among students in the sample and other factors.