English learners (ELs) are a growing demographic in schools nationwide. ELs are expected to demonstrate proficiency in core subjects like their non-EL counterparts. However, an achievement gap exists. To address the achievement disparity for ELs, schools seek certified ESOL (English to Speakers of Other Languages) teachers to provide the support ELs need to be successful. Teachers may obtain ESOL certification through endorsement, which requires extensive coursework, or through an assessment. Scholars argue that ESOL endorsed teachers are better equipped to support the academic needs of ELs. This study employed a quantitative design to determine the relationship between EL students' achievement on the Georgia Milestones in English language arts (ELA) and mathematics (MA) based on their ESOL teacher's certification pathway (coursework endorsed versus test-only certification) for a sample of students in grades six to eight. Data analysis consisted of descriptive and inferential analysis, t-test, effect size calculation, and chi-square test. The data showed there was no association between teacher certification pathway and EL student achievement for 6th-grade ELA and 8th-grade MA, and that both 6th- and 7th-grade MA had weak associations between teacher certification pathway and EL student achievement. Students in seventh and eighth-grade ELA both had moderate associations between teacher certification pathway and EL student achievement. As the results were inconclusive regarding which pathway, endorsed versus test-only, was more influential in impacting student achievement, the study concluded with recommendations regarding instructional support for ELs. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]