Five cohorts of students (N = 322) who completed a K-5 Spanish Dual Language Immersion (DLI) program in an urban school district were followed longitudinally through middle and high school completion. Academic and language achievement data included English Language Arts and Mathematics scores on the Standardized Testing and Reporting (STAR) test for grades 3-8 and on the California Assessment of Student Performance and Progress (CAASPP) for 11th grade, 10th-grade cumulative high school grade point average, enrollment in and grades earned in language classes, and attainment of the California Seal of Biliteracy. The DLI students were compared to non-DLI students who attended the same schools. Most DLI students continued with advanced level classes in Spanish in high school, and nearly half earned the California Seal of Biliteracy. Achievement results indicate that DLI graduates performed at equivalent or higher levels than non-DLI students on standardized achievement measures for English Language Arts and Mathematics.