This study employs an exploratory descriptive quantitative statistics design. District-level results in the State of Texas Assessments of Academic Readiness (STAAR) are explored to describe the achievement gaps that exist in districts implementing Transitional Bilingual Education (TBE) programs and districts implementing Dual Language (DL) programs. The study explores emergent bilingual (EB) students' mean STAAR performance in high-performing districts implementing TBE by disaggregating EB students' performance data from the districts' performance. High-performing districts are those that received an 'A' rating in the 2018-2019 A-F Accountability System in Texas. EB students' performance data is aggregated across districts and across regions to describe the achievement gaps that exist despite the high-performing 'A' rating. The study uses the districts' and EB students' mean STAAR performance for 3rd - 5th grade in Reading Language Arts (RLA), Math, and Science as recorded in the publicly accessible Texas Academic Performance Reports (TAPR). The following questions guide the study: (1) What is the STAAR achievement gap between the districts' mean performance and the mean performance of EB students when they participate in high-performing districts with TBE programs?; (2) What is the STAAR achievement gap between the districts' mean performance and the mean performance of EB students when they participate in districts with DL programs, regardless of accountability rating?; and (3) How does the STAAR achievement gap of the districts' mean performance and the mean performance of EB students in high-performing districts with TBE programs compare to the STAAR achievement gap of the districts' mean performance and the mean performance of EBs in DL programs? This study uses achievement gap metrics (Ho & Reardon, 2012; Rodriguez et al., 2016; Stevens, 2017) to analyze the data found in the TAPR and describe the achievement gaps that exist between districts' STAAR mean performance of EB students from 'A' rated districts implementing TBE and the districts' mean performance of EB students from DL programs. The findings, presented at the state, region, and district level, reveal a large achievement gap between the districts' mean performance and the EB students mean performance in 'A' rated districts implementing TBE programs. In comparison, the findings show a smaller achievement gap between the districts' mean performance and the EBs mean performance in districts implementing DL programs, regardless of their district accountability rating. A higher percentage of districts implementing DL programs show that EBs outperform the districts' mean performance when compared to 'A' rated districts implementing TBE. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]